You want to send postcards to 15 friends. In the shop there are only 3 kinds of postcards. In how many ways can you send the postcards, if

Answers

Answer 1

Answer:

455 ways

Step-by-step explanation:

Given

[tex]n = 15[/tex] --- friends

[tex]r = 3[/tex] -- available postcard kinds

Required

Ways of sending the cards

The question is an illustration of combination and the formula is:

[tex]^nC_r = \frac{n!}{(n - r)!r!}[/tex]

So, we have:

[tex]^{15}C_3 = \frac{15!}{(15 - 3)!3!}[/tex]

[tex]^{15}C_3 = \frac{15!}{12!*3!}[/tex]

Expand

[tex]^{15}C_3 = \frac{15*14*13*12!}{12!*3*2*1}[/tex]

[tex]^{15}C_3 = \frac{15*14*13}{3*2*1}[/tex]

[tex]^{15}C_3 = \frac{2730}{6}[/tex]

[tex]^{15}C_3 = 455[/tex]


Related Questions

if my child had 115 of 149 questions right what percentage is the grade

Answers

Answer:

77.18%

Step-by-step explanation:

115:149*100 =

(115*100):149 =

11500:149 = 77.18

I am having trouble with this problem. If anyone could help that would be great.
Let M be the capped cylindrical surface which is the union of two surfaces, a cylinder given by x^2+y^2=16, 0≤z≤1, and a hemispherical cap defined by x^2+y^2+(z−1)^2=16, z≥1. For the vector field F=(zx+z^2y+4y, z^3yx+3x, z^4x^2), compute ∬M(∇×F)⋅dS in any way you like.

Answers

Answer:

Ok... I hope this is correct

Step-by-step explanation:

Let M be the capped cylindrical surface which is the union of two surfaces, a cylinder given by x^(2)+y^(2)=16

Center:  ( 0 , 0 )

Vertices:  ( 4 , 0 ) , ( − 4 , 0 )

Foci:  ( 4 √ 2 , 0 ) , ( − 4 √ 2 , 0 )

Eccentricity:  √ 2

Focal Parameter:  2 √ 2

Asymptotes:  y = x ,  y = − x

Then 0≤z≤1, and a hemispherical cap defined by x^2+y^2+(z−1)^2=16, z≥1.

Simplified

0 ≤ z ≤ 1 , x ^2 + y ^2 + z ^2 − 2 ^z + 1 = 16 , z ≥ 1

For the vector field F=(zx+z^2y+4y, z^3yx+3x, z^4x^2), compute ∬M(∇×F)⋅dS in any way you like.

Vector:

csc ( x )  ,  x = π

cot ( 3 x )  ,  x = 2 π 3

cos ( x 2 )  ,  x = 2 π

Since  

( z x + z ^2 y + 4 y , z ^3 y x + 3 x , z ^4 x ^2 )  is constant with respect to  F , the derivative of  ( z x + z ^2 y + 4 y , z ^3 y x + 3 x , z ^4 x 2 )  with respect to  F  is  0 .

remove bracket and simplify 6x-(3x+2)​

Answers

Answer: 3x - 2

Step-by-step explanation:

First to solve this, we need to know some basic information such as:

1. (-) × (-) = +

2. (+) × (-) = -

3. (+) × (+) = +

Therefore, 6x-(3x+2)​

= 6x - 3x - 2

= 3x - 2

The answer to the question after removing the bracket will be 3x - 2.

The function f is defined by the following rule. f(x) = 5x+1 Complete the function table.

Answers

Answer:

[tex]-5 \to -24[/tex]

[tex]-1 \to -4[/tex]

[tex]2 \to 11[/tex]

[tex]3 \to 16[/tex]

[tex]4 \to 21[/tex]

Step-by-step explanation:

Given

[tex]f(x) = 5x + 1[/tex]

Required

Complete the table (see attachment)

When x = -5

[tex]f(-5) = 5 * -5 + 1 = -24[/tex]

When x = -1

[tex]f(-1) = 5 * -1 + 1 = -4[/tex]

When x = 2

[tex]f(2) = 5 * 2 + 1 = 11[/tex]

When x = 3

[tex]f(3) = 5 * 3 + 1 = 16[/tex]

When x = 4

[tex]f(4) = 5 * 4 + 1 = 21[/tex]

So, the table is:

[tex]-5 \to -24[/tex]

[tex]-1 \to -4[/tex]

[tex]2 \to 11[/tex]

[tex]3 \to 16[/tex]

[tex]4 \to 21[/tex]

Olivia rides her scooter 3/4 mile in
1/3 hour. How fast, in miles per hour,
does she ride her scooter?

Answers

Answer:

2.25 miles per hr

Answer:

2.25 miles per hour

Step-by-step explanation:

speed = distance / time

speed = [tex]\frac{3}{4} / \frac{1}{3}[/tex] (take the reciprocal of [tex]\frac{1}{3}[/tex])

= [tex]\frac{3}{4} * 3[/tex]

= [tex]\frac{9}{4}[/tex] = 2.25 miles per hour

Can I get the answer for those

Answers

Answer:

1) 5.64

2) 17.321

1) [tex]\frac{21}{28}[/tex]

2) [tex]\frac{16}{34}[/tex]

3) [tex]\frac{28}{35}[/tex]

4) [tex]\frac{32}{24}[/tex]

Step-by-step explanation:

SOH - CAH - TOA

Sin = [tex]\frac{O}{H}[/tex]   Cos = [tex]\frac{A}{H}[/tex]  Tan = [tex]\frac{O}{A}[/tex]      

O = opposite, A = adjacent, H = hypotenuse

First two,  use Pythagorean Theorem

If you want to calculate the angle on the last 4, use inverse of function and put in the ratio.

For example :

1) Tan Z = [tex]\frac{21}{28}[/tex]

   [tex]Tan^{-1}[/tex] ( [tex]\frac{21}{28}[/tex])

Z = 36.9°

જ્યારે જહાંગીરની ઉંમર 18 વર્ષ થશે ત્યારે અકબરની ઉંમર 50 વર્ષ થર્શ.
જ્યારે અકબરની ઉંમર જહાંગીરની ઉંમર કરતા 5 ઘણી હશે ત્યારે
અકબરની ઉમર કેટલી હશે?
A) 36
B) 40
C) 44
D) 48

Answers

Answer:

C: 44

Step-by-step explanation:

1^2 +2^2+••••+n^2=1/6n(n+1)(2n+1)
using maths induction ​

Answers

Hello,

[tex]if\ n=1\ then\ 1^2=1\ and\ \dfrac{1}{6}*1*2*3=1:\ true\ for\ n=1\\[/tex]

We suppose the property true for n:

1²+2²+...+n²=n(n+1)(2n+1) / 6

and we are going to demonstrate that the property is true for n+1:

1²+2²+..+(n+1)²=(n+1)*(n+2)*(2n+3)/6

[tex]1^2+2^2+...+n^2+(n+1)^2\\\\=n*(n+1)*(2n+1)/6+(n+1)^2\\\\=(n+1)/6*[n(2n+1)+6n+6]\\\\=(n+1)/6*(2n^2+7n+6)\\\\=(n+1)(n+2)(2n+3)/6\\[/tex]

A simple random sample of students could be achieved by stopping every other student who enters the library.
a. True
b. False

Answers

True simple random sample of student could be achieved by stopping every other student who enters the library

Brian, the gorilla, was planning a party for his zoo friends. He sent his elves Jamie and Nancy into the North Pole exhibit to count the penguins and reindeer. Jamie said there were 40 legs and Nancy said there were 14 heads. How many penguins and reindeer were in the exhibit?

Answers

Answer:

There are 8 penguins and 6 reindeers.

Step-by-step explanation:

Since Brian, the gorilla, was planning a party for his zoo friends, and he sent his elves Jamie and Nancy into the North Pole exhibit to count the penguins and reindeer, and Jamie said there were 40 legs and Nancy said there were 14 heads To determine how many penguins and reindeer were in the exhibit, the following calculation must be performed:

Penguins: 1 head and 2 legs

Reindeers: 1 head and 4 legs

40 - (14 x 2) = X

40 - 28 = X

12 = X

 

12/2 = 6

14 - 6 = 8

8 x 2 + 6 x 4 = X

16 + 24 = X

40 = X

Therefore, there are 8 penguins and 6 reindeers.

In a survey, 24 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $42 and standard deviation of $2. Construct a confidence interval at a 98% confidence level.

Answers

Answer:

The 98% confidence interval for the mean amount spent on their child's last birthday gift is between $40.98 and $43.02.

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 24 - 1 = 23

98% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 23 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.98}{2} = 0.99[/tex]. So we have T = 2.5

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 2.5\frac{2}{\sqrt{24}} = 1.02[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 42 - 1.02 = $40.98.

The upper end of the interval is the sample mean added to M. So it is 42 + 1.02 = $43.02.

The 98% confidence interval for the mean amount spent on their child's last birthday gift is between $40.98 and $43.02.

Write the rule that describes the first transformation?
RED —> BLUE

Answers

Looking at Point A to A', the rectangle moves 5 places to the left which is the x value + 5 and it shifts 1 place down which would be the y value - 1

This gets written as:

(x+5, y-1)

Round 0.485 to the nearest hundredth

Answers

Decimals start at tenths, then hundredths, then thousandths, and so on. When we round, we look at the place value that is one smaller than the one we want to round to.

So, let's take a look at the thousandths place in 0.485. The value in the thousandths place is 5. When rounding, if the value is 5 or over we round up and if the value is 4 or lower we round down. Since the value in the thousandths place is 5, we will round the hundredths place up one.

0.485 rounded to the nearest hundredth is 0.49

Hope this helps!

Answer:

0.49

Step-by-step explanation:

[tex]0<x<5=[/tex] Round down

[tex]x\geq5=[/tex] Round up

In this case, it's a round up, so the answer would be...

0.49

Hope this helped! Please mark brainliest!

HELPP
-1-3(5m+8) ≥-85
i need help :D

Answers

Answer:

- 1 - 3(5m + 8) ≥ -85

-1 - 15m - 24 ≥ -85

-15m ≥ -85 + 1 + 24

-15m ≥ 25 - 85

-15m ≥ -60

(-1)(-15)m ≤ -60(-1)

15m ≤ 60

m ≤ 4

09:30 am - 4:30 pm minus 30 minutes?
How many hours is that ?

Answers

0.9.30 am to 4.30 p.m. is 7 hours.

If we minus 30 minutes from it then it is 6 hours 30 minutes.

What does y equal in the solution of the system of equations below? 5y-3x-4z=22 2z-2x=-6 2z+3x=-6

Answers

9514 1404 393

Answer:

  y = 2

Step-by-step explanation:

Subtracting the second equation from the third gives ...

  (2z +3x) -(2z -2x) = (-6) -(-6)

  5x = 0

  x = 0

Using this in the third equation, we have ...

  2z +0 = -6

  z = -3

And substituting these values into the first equation, we have ...

  5y -3(0) -4(-3) = 22

  5y = 10 . . . . . subtract 12

  y = 2

__

The solution to the system is (x, y, z) = (0, 2, -3).

The difference between seven times a number and 9 is equal to five times
the sum of the number and 2. Find the number. Hint: There will be
parenthesis in your equation.

Answers

Answer:

The number is 9.5

Step-by-step explanation:

Look at the picture above, it explains everything

Read the following scenario, and then answer the question.

Juan assumes that the temperature of the hot tea cooling on his desk can be modeled with an exponential function like this one: T(t)=179(0.92)t. He bases his assumption on the following: The tea cools about 8% every minute. The tea's current temperature is around 179 degrees Fahrenheit.

Which explanation correctly addresses Juan's assumption?

He is incorrect. The tea will cool linearly since it cools at the same number of degrees every minute.
He is correct. The tea will cool exponentially since it cools at a percentage rate every minute.
He is incorrect. The tea will cool along the curve of a parabola since it cools at an increasing percentage rate every minute.

Answers

9514 1404 393

Answer:

  (b)  He is correct. The tea will cool exponentially since it cools at a percentage rate every minute.

Step-by-step explanation:

Newton's Law of Cooling says the change in temperature is proportional to the temperature. This relation gives rise to an exponential function describing the temperature.

In this description, the temperature referred to is the difference between the temperature of the object and the temperature of the environment to/from which heat is being transferred.

Juan is only partially correct. The function is exponential, but the temperature that should be used in his equation is not the temperature of the tea, but the temperature difference between the tea and his desk.

__

The curve is not linear and not parabolic, excluding the other answer choices.

Which terms in the following expression are like terms?

x3 + 5x - 3x + 3y + 4 - 1

3x and 3y
x 3, 3x, and 3y
5x and 3x, and 4 and 1
x 3 and 3x, and 4 and 1

Answers

9514 1404 393

Answer:

  (c)  5x and 3x, and 4 and 1

Step-by-step explanation:

Like terms have the same variable(s) to the same power(s).

The terms of this expression are ...

x^3: variable x, power 35x: variable x, power 1-3x: variable x, power 13y: variable y, power 14: no variable-1: no variable

The like terms are {5x, -3x}, which have the x-variable to the first power, and {4, -1}, which have no variable.

A scientist claims that 4% of viruses are airborne. If the scientist is accurate, what is the probability that the proportion of airborne viruses in a sample of 662 viruses would be greater than 6%

Answers

Answer:

The probability that the proportion of airborne viruses in a sample of 662 viruses would be greater than 6%=0.00427

Step-by-step explanation:

We are given that

[tex]\mu_{\hat{p}}=p=4%=0.04[/tex]

n=662

We have to find the probability that the proportion of airborne viruses in a sample of 662 viruses would be greater than 6%.

q=1-p=1-0.04=0.96

[tex]\sigma_{\hat{p}}=\sqrt{p(1-p)/n}[/tex]

[tex]\sigma_{\hat{p}}=\sqrt{\frac{0.04(1-0.04)}{662}}[/tex]

[tex]\sigma_{\hat{p}}=0.0076[/tex]

Now,

[tex]P(\hat{p}>0.06)=1-P(\hat{p}<0.06)[/tex]

[tex]=1-P(\frac{\hat{p}-\mu_{\hat{p}}}{\sigma_{\hat{p}}}<\frac{0.06-0.04}{0.0076})[/tex]

[tex]=1-P(Z<2.63)[/tex]

[tex]=1-0.99573[/tex]

[tex]P(\hat{p}>0.06)=0.00427[/tex]

Hence, the probability that the proportion of airborne viruses in a sample of 662 viruses would be greater than 6%=0.00427

A case of 6 cost 7.5 what it the price per item

Answers

1.25 hope this helps

A teacher has a 2-gallon (52 cup) container of juice. She gives each student z cup of juice. Which equation represents the amount of juice that remains, y, after x students are served?

Answers

Answer:

[tex]y = 32 - \frac{1}{2}x[/tex]

Step-by-step explanation:

Given

[tex]Cups = 32[/tex] ---- not 52

[tex]Students = x[/tex]

[tex]Remainder = y[/tex]

[tex]Each = \frac{1}{2}[/tex] --- not z

Required

The equation for y

The remainder y is calculated as:

[tex]y = Cups - Students * Each\\[/tex]

[tex]y = 32 - \frac{1}{2}x[/tex]

______are used to represent an unknown quantity in a mathematical expression.

Answers

Answer:

Variables are used to represent an unknown quantity in a mathematical expression.

Step-by-step explanation:

Variables are used to represent an unknown quantity in a mathematical expression.For example : x + 2 = 4, here x is the variable.We can denote variable by any alphabet i.e, a,b,c,d etc.

Given n(A) = 1300, n(A U B) = 2290, and n(A n B) = 360, find n(B).

Answers

Answer:

n(B) = 1350

Step-by-step explanation:

Using Venn sets, we have that:

[tex]n(A \cup B) = n(A) + n(B) - n(A \cap B)[/tex]

Three values are given in the exercise.

The other is n(B), which we have to find. So

[tex]n(A \cup B) = n(A) + n(B) - n(A \cap B)[/tex]

[tex]2290 = 1300 + n(B) - 360[/tex]

[tex]940 + n(B) = 2290[/tex]

[tex]n(B) = 2290 - 940 = 1350[/tex]

So

n(B) = 1350

Solve the equation x^2+6x+1=0

Answers

Hello!

x² + 6x + 1 = 0 <=>

<=> x = -6±√6²-4×1×1/2×1 <=>

<=> x = -6±√36-4/2 <=>

<=> x = -6±√32/2 <=>

<=> x = -6±2²√2/2 <=>

<=> x = -6±4√2/2 <=>

<=> x = -6+4√2/2 <=>

and

<=> x = -6-4√2/2 <=>

<=> x = -3+2√2 <=>

and

<=> x = -3-2√2 <=>

x1 = -3-22 and x2 = -3+22

Good luck! :)

X^2+6X+1=0
X^2+6X+3^2-3^2+1=0
(X+3)^2-9+1=0
(X+3)^2=8
X+3= ± 2√2
X= ±2√2-3

1. S = 10 mm
V= S×S×S
=___×___×___
=____ mm3

Answers

Hi there!  

»»————- ★ ————-««

I believe your answer is:  

[tex]V=1000\text{mm}^3[/tex]

»»————- ★ ————-««  

Here’s why:  

⸻⸻⸻⸻

I am assuming by the infomation given that the figure is a cube.

⸻⸻⸻⸻

[tex]\boxed{\text{Finding the volume of the cube...}}\\\\S = 10mm; V= s^3\\--------------\\\rightarrow V = 10^3\\\\\rightarrow V = 10 * 10 * 10\\\\\rightarrow \boxed{V=1000\text{mm}^3}[/tex]

⸻⸻⸻⸻

»»————- ★ ————-««  

Hope this helps you. I apologize if it’s incorrect.  

Please answer!<333 xx

Answers

12. X= 6

14. B= -11

16. N= 15

Answer:

q12. [tex]x=6[/tex]

q14. [tex]b=-11[/tex]

q16. [tex]n=15[/tex]

Step-by-step explanation:

Q12.

[tex]-1=\frac{x}{-6}[/tex]

Flip the equation:

[tex]\frac{x}{-6} =-1[/tex]

Multiply both sides by 6/(-1)

[tex](\frac{6}{-1} )[/tex] × [tex](\frac{-1}{6}x )[/tex] = [tex](\frac{6}{-1} )[/tex] × [tex](-1)[/tex]

[tex]x=6[/tex]

Q14.

[tex]5b=-55[/tex]

[tex]b=\frac{-55}{5}[/tex]

[tex]b=-11[/tex]

Q16.

[tex]-3n=-45[/tex]

[tex]n=\frac{-45}{-3}[/tex]

[tex]n=15[/tex]

hope this helps.....

Ralph bought a computer monitor with an area of 384 square inches. The length of the monitor is six times the quantity of five less than half its width.

Complete the equation that can be used to determine the dimensions of the monitor in terms of its width, w.

Answers

Answer:

w= 103.5 inches

Step-by-step explanation:

384=w+3w-30

414=4w

w=414/4=103.5 inches

Answer:

first drop box 384

second drop box 3

third drop boc 30

384 = 3 [tex]w^{2}[/tex] – 30 w

Step-by-step explanation:

Correct answer on Plato/Edmentum test

A student has test scores of 75 and 82respectively. What is the student’s average score for a third test

Answers

Answer:

78.5 (I think 90% sure)

Step-by-step explanation:

sum of both scores

75+82 = 157

average for a third test

157÷2=78.5

Which statements below represent the situation? Select three options.

Answers

Answer:

where is the statement

Step-by-step explanation:

its incomplete po

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