There are 4 windows in the living room. Each window has 1 set of blinds and 2 panels of curtains. The blinds cost $20 each. Each curtain panel cost $28. How much do the window treatments cost?

Answers

Answer 1
4X2=8 8x28= 224
4x20= 80
80+224=304


$304 total
Answer 2

Answer:

$304

Step-by-step explanation:

4 Windows (each window has 1 blind and 2 panels of curtains)

1 blind = $20 * 4 = $80

1  panels curtains = $28 * 2 = $56 * 4 = $224

$80 + $224 = $304


Related Questions

88, 92, 76, 42, 88, 90, 100, 110, 115, 5, 88, 92, 95
Find the Mean, Median, Mode, Range and Outlier of the data set above?

Answers

Answer:

Mean = 83.15

Median = 90

Mode = 88

Range = 110

Outlier = 5

Step-by-step explanation:

Mean - (88+92+76+42+88+90+100+110+115+5+88+92+95)/2 = 83.15

Median - 5, 42, 76, 88, 88, 88, 90, 92, 92, 95, 100, 110, 115 = 90

Mode - 88, 92, 76, 42, 88, 90, 100, 110, 115, 5, 88, 92, 95 = 88

Range - 115 - 5 = 110.

Outlier - 88, 92, 76, 42, 88, 90, 100, 110, 115, 5, 88, 92, 95 = 5

hope it helps :)

please mark brainliest!!! (took a lot effort!)

Answer:

Step-by-step explanation:

Arrange the data from the lowest to the highest value ( after you rearrange them count to see if you still have the same amount of values -13 numbers)

5, 42, 76, 88, 88, 88, 90, 92, 92, 95, 100, 110, 115

Mean: sum up all the values /number of values

mean = (5+42+76+88+88+88+90+92+92+95+100+110+115)/13 ≅83.15

Median: is the number in the middle (or if you have an even amount of numbers you do the average of the 2 middle numbers)

median = 90

Mode: is the number that appears the most (a data set can have more than one mode if different numbers appear with the same frequency )

mode= 88

Range: is the difference between the biggest and smallest value

range = 115-5 = 110

Outlier: is a value that is significantly different than the rest of the values

outlier = 5

Find the value of x. Show your work with proper statements and notation

Answers

Answer:  x = 14

====================================================

Explanation:

For any triangle, the three inside or interior angles always add to 180

M+N+P = 180

32+64+6x = 180

6x+96 = 180

6x = 180-96

6x = 84

x = 84/6

x = 14

If it's possible to tell, decide if a and b are positive or negative: a-3>b-3 and b>4

PLEASE HELP NEED ASAPPPPPPP

Answers

Answer:

a and b are positive

Step-by-step explanation:

We are given that

[tex]a-3>b-3[/tex]

[tex]b>4[/tex]

We have to find that a and b are positive or negative.

We have

[tex]b>4[/tex]

It means b is positive and greater than 4.

[tex]a-3>b-3[/tex]

Adding 3 on both sides

[tex]a-3+3>b-3+3[/tex]

[tex]a>b>4[/tex]

[tex]\implies a>4[/tex]

Hence, a is positive and greater than 4.

Therefore, a and b are positive

Bailey wants to buy a house, paying approximately $1000 per month. The bank estimates a 4.5% annual interest rate for 15 years. Which formula approximates the total value of a house Bailey can afford?
A. P = 1000[1 - (1 + 0.045/12)^-180/0.045/12.
B. P = 1000(0.045/12)/1 - 1(1 + 0.045/12)^-180.
C. 1000 = d[1 -(1 + 0.045/12)/0.045/12]^-180.
D. 1000 = d(0.045/12)/1 -(1 + 0.045/12)^180.

Answers

Answer:

I=Principle × Rate × Time so 1000×4.5/100 × 15yrs

easy! please help :( The top shelf of a bookcase holds 6 fiction and 4 nonfiction books. On the bottom shelf are 3 fiction and 5 nonfiction books.
Choosing which 2 books describes a pair of dependent events?

Answers

Answer:

D: one of the non-fiction books on the bottom shelf and a second non-fiction book from the bottom shelf

Step-by-step explanation:

A pair of 2 dependent events are simply those in which the choice of the second item depends on taking the first item such that the probability changes.

Because when the first item is taken without replacement, the sample size would have reduced and as such picking the exact same item will reduce the probability.

Now, what this means in relation to the question is that for 2 of the events to be independent, they must be on the same shelf and of same type of book such that the second book can't be selected until the first one has been selected.

The only option that fits this definition is option D where both books are on the same shelf and they are same type of books.

Answer:

one of the nonfiction books on the bottom shelf, and a second nonfiction book from the bottom shelf

Step-by-step explanation:

Please help I really don’t understand anything at all !

Answers

Answer:

see explanation

Step-by-step explanation:

1

2(3x + 1) = 4(x + 2) ← distribute parenthesis on both sides

6x + 2 = 4x + 8 ( subtract 4x from both sides )

2x + 2 = 8 ( subtract 2 from both sides )

2x = 6 ( divide both sides by 2 )

x = 3

------------------------------------------------------------

2

6x = 4(x - 3) ← distribute parenthesis

6x = 4x - 12 ( subtract 4x from both sides )

2x = - 12 ( divide both sides by 2 )

x = - 6

-----------------------------------------------------------

3

2(4x + 7) = 4x + 30 ← distribute parenthesis on left side

8x + 14 = 4x + 30 (subtract 4x from both sides )

4x + 14 = 30 ( subtract 14 from both sides )

4x = 16 ( divide both sides by 4 )

x = 4

---------------------------------------------------------------------

4

50 = - (y + 22) ← distribute parenthesis by - 1

50 = - y - 22 ( add 22 to both sides )

72 = - y ( multiply both sides by - 1 )

- 72 = y , that is

y = - 72

1/2-5(2/3x + 6)+4/5x?

Answers

Answer:

[tex]-29.5-\frac{38}{15}x[/tex]

Step-by-step explanation:

First, we must expand out the -5.

-5 times 2/3x is equal to -10/3x, and -5 times 6 is equal to -30. 1/2 minus 30 is equal to -29.5, and 4/5x minus 10/3x is equal to -38/15x.

Suppose 5 men and 7 women are on a crowded elevator. At the next floor, four people get off the elevator. Find the probability that three are women.

0.010

0.354

0.424

0.25

Answers

Total People=5+7+4=16

Women=7

We know

[tex]\boxed{\sf P(W)=\dfrac{No.\:of\:women}{Total\:People}}[/tex]

[tex] \\ \sf \longmapsto \: p(w) = \frac{7}{16} [/tex]

the area for this shape.

Answers

Answer:

240 cm

Step-by-step explanation:

10 • 18 = 180

18 - 6 = 12

12 • 5 = 60/2 = 30

12 • 5 = 60/2 = 30

180 + 30 + 30 = 240

Answer:

Step-by-step explanation:

Suppose a rumor is going around a group of 210 people. Initially, only 34 members of the group have heard the rumor, but 3 days later 69 people have heard it. Using a logistic growth model, how many people are expected to have heard the rumor after 6 days total have passed since it was initially spread? (Round your answer to the nearest whole person.)

Answers

Answer:

116 people are expected to have heard the rumor after 6 days total have passed since it was initially spread.

Step-by-step explanation:

Logistic function:

The logistic function is given by:

[tex]P(t) = \frac{K}{1 + Ae^{-kt}}[/tex]

In which:

[tex]A = \frac{K - P(0)}{P(0)}[/tex]

Considering that K is the carrying capacity, k is the growth/decay rate and P(0) is the initial population.

Suppose a rumor is going around a group of 210 people.

This means that [tex]K = 210[/tex]

Initially, only 34 members of the group have heard the rumor:

This means that [tex]P(0) = 34[/tex] and:

[tex]A = \frac{210 - 34}{34} = 5.1765[/tex]

So

[tex]P(t) = \frac{210}{1 + 5.1765e^{-kt}}[/tex]

3 days later 69 people have heard it.

This means that [tex]P(3) = 69[/tex], and we use this to find k.

[tex]69 = \frac{210}{1 + 5.1765e^{-3k}}[/tex]

[tex]69 + 357.1785 e^{-3k} = 210[/tex]

[tex]357.1785 e^{-3k} = 141[/tex]

[tex]e^{-3k} = \frac{141}{357.1785}[/tex]

[tex]\ln{e^{-3k}} = \ln{\frac{141}{357.1785}}[/tex]

[tex]-3k = \ln{\frac{141}{357.1785}}[/tex]

[tex]k = -\frac{\ln{\frac{141}{357.1785}}}{3}[/tex]

[tex]k = 0.3098[/tex]

So

[tex]P(t) = \frac{210}{1 + 5.1765e^{-0.3098t}}[/tex]

How many people are expected to have heard the rumor after 6 days total have passed since it was initially spread?

This is P(6), so:

[tex]P(6) = \frac{210}{1 + 5.1765e^{-0.3098*6}} = 116[/tex]

116 people are expected to have heard the rumor after 6 days total have passed since it was initially spread.

Where A = -7 and b = 9 what is the value of the midpoint?

Answers

Answer:

Find the value of x if B is the midpoint of AC, AB = 2x + 9 and BC = 37

Step-by-step explanation:

Solve for x.
A. 1
B. 4
C. 7
D. 9

Answers

9514 1404 393

Answer:

  B.  4

Step-by-step explanation:

The product of segment lengths to the near and far circle intercepts is the same for both secants.

  5(5 +(x-1)) = 4(4 +(x+2))

  5(x +4) = 4(x +6) . . . . . simplify inside parentheses

  5x +20 = 4x +24 . . . eliminate parentheses

  x = 4 . . . . . . . . . . . . subtract 20+4x

What is the length of AB?
.
A9
B. 3
C.
0.
D. 12

Answers

Answer:

D

Step-by-step explanation:

4X =2 X +6

=>X =  3

= 2x+6+4x=80°= 6x=80°-6 = 6x=74°= x=74°÷6= x=12.33

answer is d=12

URGENT 100 POINTS AND BRAINIEST
Question 9 (Essay Worth 10 points)
(04.01, 04.02 HC)

Ted practices two types of swimming styles for a total of 50 minutes every day. He practices the breaststroke for 20 minutes longer than he practices the butterfly stroke.

Part A: Write a pair of linear equations to show the relationship between the number of minutes Ted practices the butterfly stroke every day (x) and the number of minutes he practices the breaststroke every day (y). (5 points)

Part B: How much time does Ted spend practicing the breaststroke every day? Show your work. (3 points)

Part C: Is it possible for Ted to have spent 45 minutes practicing the butterfly stroke if he practices for a total of exactly 50 minutes and practices the breaststroke for 20 minutes longer than he practices the butterfly stroke? Explain your reasoning. (2 points)

Answers

Answer:

Part A:

x + y = 50

y = x + 20

Part B:

Ted spends 35 minutes practicing the breaststroke every day.

Part C: It is not possible, as 45 + 65 isn't 50.

Step-by-step explanation:

Write an equation for a line containing (–2,8) that is perpendicular to the line containing the points (3,–4)and (–7,1).





Answer and I will give you brainiliest

Answers

Answer:

y = 2x + 12

Step-by-step explanation:

the formula for a line is typically

y = ax + b

a is the slope of the line (expressed as y/x ratio describing how many units y changes, when x changes a certain amount of units).

b is the offset of the line in y direction (for x=0).

we have the points (3, -4) and (-7, 1).

to get the slope of the line let's wander from left to right (x direction).

to go from -7 to 3 x changes by 10 units.

at the same time y changes from 1 to -4, so it decreases by 5 units.

so, the slope is -5/10 = -1/2

and the line equation looks like

y = -1/2 x + b

to get b we simply use a point like (3, -4)

-4 = -1/2 × 3 + b

-4 = -3/2 + b

-5/2 = b

so, the full line equation is

y = -1/2 x - 5/2

now, for a perpendicular line the slope exchanges x and y and flips the sign.

in our case this means +2/1 or simply 2.

so, the line equation for the perpendicular line looks like

y = 2x + b

and to get b we use the point we know (-2, 8)

8 = 2×-2 + b

8 = -4 +b

12 = b

so, the full equation for the line is

y = 2x + 12

Answer:

2x-y+12= 0 or y = 2x+12 is the answer

Step-by-step explanation:

slope of the line joining (3,-4) and (-7,1) is 1-(-4)/-7-3

= -5/10

= - 1/2

slope of the line containing (-2,8) and that is perpendicular to the line containing (3,-4) and (-7,1) = 2

Equation of the line line containing (-2,8) and that is perpendicular to the line containing (3,-4) and (-7,1) is y-8 = 2(x-(-2))

y-8 = 2(x+2)

y- 8 = 2x+4

y=2x+12 (slope- intercept form) or 2x-y+12= 0 (point slope form)

what is 32⋅(12)x+1=2x−14?

Answers

Answer:

[tex]x=-\frac{15}{382}[/tex]

Step-by-step explanation:

32 × 12x + 1 = 2x - 14

384x + 1 = 2x - 14

384x + 1 - 1 = 2x - 14 - 1

384x = 2x - 15

384x - 2x = 2x - 2x - 15

382x = - 15

382x ÷ 382 = - 15 ÷ 382

[tex]x=-\frac{15}{382}[/tex]

Help please so lost!!!!!!!!!!!!

Answers

Answer:

hmmmmm please send the pic again

Select the correct answer
The equation of a line is y= 15x-2 What are its slope and y-intercept?
A.slope = 15 and y-intercept=-2
B.slope = 15 and y-intercept = 2
C.slope = 2 and y-intercept=15
D.siope =-2 and y-intercept=15
RES

Answers

Answer:

A

Step-by-step explanation:

Slope = term that multiply x

y intercept = the number without a variable

total number of chocolate boxes that can be produced: x+y (<,<=,>,>=) ___
restrictions based on demand of each: y(<,<=,>,>=) ___x
maximum amount of white chocolate production: y(<,<=,>,>=) ____
minimum amount of milk chocolate production: x(<,<=,>,>=) ____
minimum amount of white chocolate production: y(<,<=,>,>=) ____
vertices of feasible region : (0,0)(400,___)(____,___)(___,0)
optimization equation: profit = ____x+____y
your maximum profit is $____ .you should produce ____ boxes of milk chocolate and ____ boxes of white chocolate .

Answers

Answer:

Step-by-step explanation:

The idea here is to create lines according to the constraints we were given, graph the lines (which are actually inequalities), and then shade in the region that satisfies the inequality. Let's start at the beginning of the problem and we'll get our lines (inequalities) written.

The total number of boxes that can be produced according to the constraints is 800, so the inequality for that is

x + y ≤ 800 and solving for y:

y ≤ 800 - x

Another constraint on the white chocolate is that it has to be less than or equal to 200 boxes, so:

y ≤ 200

The max number of white chocolate boxes is half the number of milk chocolate, so:

y ≤ (1/2)x

The min number of milk chocolate boxes produced is:

x ≥ 0 and

The min number of white chocolate boxes produced is:

y ≥ 0 (This means that it is a possibility of making 0 milk chocolate boxes and all white chocolate boxes OR there is a possibility of making 0 white chocolate boxes and all milk chocolate boxes)

The production equation (which is used later) is:

2.25x + 2.50y (you make a profit of $2.25 on every milk chocolate box you sell and profit of $2.50 on every white chocolate box you sell).

The bold equations are the ones that need to be graphed (see graph below). Where those 3 lines intersect are the vertices of feasible region:

(0, 0), (400, 200), (600, 200), (800, 0).

Then take each x and y value from a coordinate and plug it into the profit equation (we don't need to use (0, 0)) starting with x = 400 and y = 200:

2.25(400) + 2.5(200) = $1400

Now using x = 600 and y = 200:

2.25(600) + 2.5(200) = $1850

Now using x = 800 and y = 0:

2.25(800) + 2.5(0) = $1800

So our max profit as seen by the evaluations is $1850, and that occurs when we sell 600 boxes of milk chocolate and 200 boxes of white chocolate.

A nut company is determining how to package their new type of party mix. The marketing department is experimenting with different-sized cans for the party mix packaging. The designers use the equation r=Vhπ⎯⎯⎯⎯⎯⎯√r=Vhπ to determine the radius of the can for a certain height hh and volume VV. The company decides they want the can to have a volume of 1280πcm31280π⁢cm3. Find the radius of the can if the height is 16cm16⁢cm. Keep your answers in simplified radical form.

Answers

Answer:

The radius of the can, in centimeters, is of [tex]4\sqrt{5}[/tex]

Step-by-step explanation:

Radius of the can:

The radius of the can is given by:

[tex]r^2 = \frac{V}{h\pi}[/tex]

In which V is the volume and h is the height.

In this question:

[tex]V = 1280\pi, h = 16[/tex]

Thus

[tex]r^2 = \frac{V}{h\pi}[/tex]

[tex]r^2 = \frac{1280\pi}{16\pi}[/tex]

[tex]r^2 = 80[/tex]

[tex]r = \sqrt{80}[/tex]

[tex]r = \sqrt{5*16}[/tex]

[tex]r = \sqrt{5}\sqrt{16}[/tex]

[tex]r = 4\sqrt{5}[/tex]

The radius of the can, in centimeters, is of [tex]4\sqrt{5}[/tex]

A barbecue grill is a circle with a diameter of 2.2 feet. What is the circumference of the grill (in feet)? (R
decimal places.)

Answers

Step-by-step explanation:

circumference =pi × diameter

=(22/7)×2.2

=6.914ft

Answer:

6.91 feet

Step-by-step explanation:

What is the simplified form of the following expression?

Answers

Answer:

-( cube root of 2x)-6(cube root of x)

A die is rolled five times and a 5 or 6 is considered a success. Find the probability of
(i) at least 2 successes,
(ii) at least one but no more than 3 successes.

Answers

Answer:

(i) The probability of at least 2 successes is 0.2093.

(ii) The probability of at least one but no more than 3 successes is 0.9548.

Step-by-step explanation:

Now the total number of cases = {1, 2, 3, 4, 5, 6} = 6.

Favourable cases = {1, 6} = 2.

[tex]p = \frac{2} {3} = \frac{1} {3} \\\\q = 1- p\\\\q = \frac{2}{3} \\\\n=5[/tex]

i) at least 2 successes,

[tex]P(X\geq 2) = (^{n}C_{x} )\times p^{x} \times (1-p)^{n-x}\\\\P(X\geq 2) = 0.2093[/tex]

ii) at least one but no more than 3 successes,

[tex]P(X\leq 3) = (^{n}C_{x} )\times p^{x} \times (1-p)^{n-x}\\\\P(X\leq 3)= 0.9548[/tex]

Josh sees a pair of trainers with a tags saying 75% off the recommended price of £80. Josh decided to buy the trainers. How many pounds will it cost him?

Answers

To find this use this formula: (percent off) / 100 x (cost)

Make a T-chart with 5 points and Graph the function below on the graph paper you have been provided with. Identify the Key features. AOS, DOMAIN, and RANGE. Make sure I can easily identify your answers on your paper. Also, answer the question below.

Answers

Answer:

look this up ok

Step-by-step explanation:

Graph axis of symmetry vertex and max and min, domain and range

Flying with a tailwind, a flight crew flew 500 km in 4 hours. Flying against the tailwind, the crew flew 468 km in 4 hours. Find the speed of the plane in calm air and the speed of the wind, both in km per hour.

Answers

Answer:

spped of the plane in calm air=121 km/h

speed of the wind= 4km/h

Step-by-step explanation:

Let say V the speed of the plane in calm air

and v the speed of the wind

Flying with a tailwind, a flight crew flew 500 km in 4 hours ==> 500= (V+v)*4

Flying against the tailwind, the crew flew 468 km in 4 hours ==> 468 = (V-v)*4

We divide the 2 equations by 4 and then add the 2 results equations:

(500+468)/4=2V ==> V=121 (km/h)

We replace that value in the first equation:

V+v=500/4=125

v=125-121=4 (km/h)

Camilla and Aisha are sisters and go to the same school. This morning, Camilla decided to bike to school, and Aisha decided to walk. They left home at the same time. Camilla’s speed was 6.5 miles per hour, and Aisha’s speed was 2 mph. When Camilla reached the school, Aisha was 1.5 miles behind. How far away from their house is the school?

Answers

Answer:

2 1/6

Step-by-step explanation:

6.5x=2x+1.6=1/3

1/3*6.5=2 1/6

Can someone help me thank youuu!!!

Answers

Answer:

D.

Step-by-step explanation:

cos is positive and sin is negative

=>

it must be in quadrant IV.

you remember, 1 = sin² + cos²

1 = sin² + (3/5)² = sin² + 9/25

25/25 = sin² + 9/25

16/25 = sin²

sin = 4/5 or -4/5

and as sin of this angle is < 0, our solution is -4/5

A shopkeeper bought a second-hand car for Rs 1,50,000. He spent Rs 10,000

on its painting and repair and then sold it for Rs 2,00,000. Find his profit or loss.

Answers

I am not sure about my answer as the placement of the zeros are confusing but hopefully it’s right

Can someone please help me with this; im a lil bit confused.... Q.solve for the values of x in the equation 2x² - 5x - 12 = 0 using the quadratic equation formula.​

Answers

Answer:

The solutions for x are [tex]x = 4[/tex] and [tex]x = -1.5[/tex].

Step-by-step explanation:

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

[tex]ax^{2} + bx + c, a\neq0[/tex].

This polynomial has roots [tex]x_{1}, x_{2}[/tex] such that [tex]ax^{2} + bx + c = a(x - x_{1})*(x - x_{2})[/tex], given by the following formulas:

[tex]x_{1} = \frac{-b + \sqrt{\Delta}}{2*a}[/tex]

[tex]x_{2} = \frac{-b - \sqrt{\Delta}}{2*a}[/tex]

[tex]\Delta = b^{2} - 4ac[/tex]

2x² - 5x - 12 = 0

This means that [tex]a = 2, b = -5, c = -12[/tex]

Solution:

[tex]\Delta = (-5)^2 - 4(2)(-12) = 121[/tex]

[tex]x_{1} = \frac{-(-5) + \sqrt{121}}{2*2} = 4[/tex]

[tex]x_{2} = \frac{-(-5) - \sqrt{121}}{2*2} = -1.5[/tex]

The solutions for x are [tex]x = 4[/tex] and [tex]x = -1.5[/tex].

Other Questions
A swimming pool has 143 gallons of water in it. The swimming pool drains at a rate of 8 gallons per minute. How much water is in the swimming pool after 11 minutes?How much water does the swimming pool have after 11 minutes? Solve on paper, then enter your answer on Zearn.The swimming pool has gallons of water after 11 minutes. Importance of alternative source of energy? In a mid-size company, the distribution of the number of phone calls answered each day by each of the 12 receptionists is bell-shaped and has a mean of 43 and a standard deviation of 8. Using the empirical rule (as presented in the book), what is the approximate percentage of daily phone calls numbering between 19 and 67 help is needed please!! Which evils of modern society does Mr. Diamond cite as evidence that the Neolithic Revolution was a negative event in the history of mankind? You've just read an article that makes claims and provides statistics you would like to use in your report. Why is it important to determine if other sources are making the same claims and citing the same statistics?To gain different perspectives and discover new ideas by examining several sourcesTo ensure that the statistics are real and the claims are generally agreed upon by expertsTo find out if the author is quoted by others on the web and establish his or her credibilityTo determine if the author's thoughts and ideas are unique and original As a skydiver accelerates downward, what force increases? A. Gravity B. Thrust C. Air resistance D. Centripetal What is the domain of the function graphed below? at the constuional convetion, the indivdual states voted to work towards the formation of a new government by using which of the following A. the new jersey plan B. the new york planC. the georgia plan D. the virginia plan Can someone please help me on these 3 equations please HELP ME !!! 5. True or False: A beginner should start with long workout sessions and work down to shorter ones.TrueFalse Please help me anyone A steep mountain is inclined 75 degree to the horizontal and rises 3900 ft above the surrounding plain. A cable car is to be installed by connecting a cable from the top of the mountain to a spot on the plain that is 910 ft from the base of the mountain. Find the shortest length of cable needed. The Underground Railroad was _____________.a.an illegal abolitionists newspaperc.a railroad used by slaves to escapeb.a subway system operated by African American conductorsd.a series of safe houses harboring runaway slaves on their journey northPlease select the best answer from the choices providedABCD please prove it (full steps required)(No spam answers) Find the APR, rounded to the nearest tenth of a percent (one decimal place) for the loan. Purchase a living room set for $4,900 at 8% add-on interest for 4 years. Enter only the number without % sign. Can anyone help me answer this An analyst has decided to identify value stocks for investment by screening for companies with high book-to-market ratios and high dividend yields. A potential drawback of using these screens to find value stocks is that the firms selected may: be those that have significantly underperformed the market. be concentrated in specific industries. have unsustainable dividend payments. this is the question hope u can solve it How to muilti step equation this problem