You have a bag which contains only red and green marbles. In this bag with $x^{2} 5$ marbles total, $x 1$ are red. Also, $x-3$ marbles have a scratch on them. The probability of drawing a red marble from the original bag is equal to that of drawing a marble with a scratch from the marbles left in the bag after twenty scratch-free marbles are taken out of the full bag. How many marbles were originally in the bag?

Answers

Answer 1

The original number of marbles in the bag is 30.

The given parameters are:

[tex]Red = x + 1[/tex]

[tex]Total = x^2 + 5[/tex]

The probability of red is:

[tex]P(Red) = \frac{Red}{Total}[/tex]

[tex]P(Red) = \frac{x+1}{x^2 + 5}[/tex]

When 20 marbles were removed, the marbles left are:

[tex]Marbles =Total - 20[/tex]

This gives:

[tex]Marbles =x^2 + 5 - 20[/tex]

[tex]Marbles =x^2 -15[/tex]

The probability of selecting a scratched marble at this point is:

[tex]P(Scratch) = \frac{Scratch}{Marbles}[/tex]

[tex]P(Scratch) = \frac{x -3}{x^2 - 15}[/tex]

This probability equals the probability of red.

i.e.

[tex]P(Red) = P(Scratch)[/tex]

So, we have:

[tex]\frac{x +1}{x^2 + 5} = \frac{x -3}{x^2 - 15}[/tex]

Cross multiply

[tex](x + 1)(x^2 - 15) = (x - 3)(x^2 + 5)[/tex]

Expand

[tex]x^3 - 15x + x^2 - 15 = x^3 + 5x - 3x^2 - 15[/tex]

Subtract [tex]x^3[/tex] from both sides

[tex]- 15x + x^2 - 15 = 5x - 3x^2 - 15[/tex]

Add 15 to both sides

[tex]- 15x + x^2 = 5x - 3x^2[/tex]

Collect like terms

[tex]3x^2 + x^2 - 15x - 5x = 0[/tex]

[tex]4x^2 - 20x = 0[/tex]

Divide through by 4

[tex]x^2 - 5x = 0[/tex]

Expand

[tex]x(x - 5) = 0[/tex]

Split

[tex]x = 0[/tex] or [tex]x - 5 = 0[/tex]

[tex]x = 0[/tex] or [tex]x = 5[/tex]

x can't be 0.

So: [tex]x = 5[/tex]

The number of marbles initially is:

[tex]Total = x^2 + 5[/tex]

[tex]Total = 5^2 + 5[/tex]

[tex]Total = 30[/tex]

Hence, the original number of marbles in the bag is 30.

Read more about probabilities at:

https://brainly.com/question/11234923


Related Questions

9 in.
13 in.
10 in
Drawing not to scale
b. 90 in?
45 in?
d. 292.5 in.
c. 32 in?
a.

Answers

Answer:

a, a, d

Step-by-step explanation:

44

The area (A) of a triangle is calculated as

A = [tex]\frac{1}{2}[/tex] bh ( b is the base and h the perpendicular height )

Here b = 10 and h = 9 , then

A = [tex]\frac{1}{2}[/tex] × 10 × 9 = 5 × 9 = 45 in² → a

45

The area (A) of a parallelogram is

A = bh ( b is the base and h the perpendicular height )

Here b = 2 and h = 4 , then

A = 2 × 4 = 8 m² → a

46

A = bh ( with b = 4 and h = 10 )

A = 4 × 10 = 40 m² → d

sin(2x-pi/2)=sin pi/3

Answers

This is the answer for your question!

Write the number 3388198 in word form

Answers

Three million three hundred eighty-eight thousand one hundred ninety-eight - 3388198

solve 3/4 (x+1)+1=1/2 (×-2)+5​

Answers

Answer:

X=5 or 3/4x-1/2x=6-1

Step-by-step explanation:

3/4(x+1)+1=1/2(x-2)+5

3/4x+1=1/2x-6

3/4x-1/2x=6-1

x=5

45.55 to 1 decimal place

Answers

Answer:

45.6

Step-by-step explanation:

45.55

We want to round to the tenths place

we look at the hundredths place

.x5  Since the number in the hundredths place is 5 or greater, we round up 1

45.55 becomes 45.6

Answer:

the answer is 45.6

Step-by-step explanation:

[tex]\sf{}[/tex]

♛┈⛧┈┈•༶♛┈⛧┈┈•༶

HURRY PLEASE!
Evaluate –5u for u = –4.

Answers

[tex]\huge\text{Hey there!}[/tex]

[tex]\huge\textsf{-5u}[/tex]

[tex]\huge\textsf{= -5(-4)}[/tex]

[tex]\huge\textsf{= 5(4)}[/tex]

[tex]\huge\textsf{= 20}[/tex]

[tex]\boxed{\boxed{\huge\text{Therefore, your answer is: \textsf{20}}}}\huge\checkmark[/tex]

[tex]\huge\textsf{Good luck on your assignment \& enjoy your day!}[/tex]

~[tex]\frak{Amphitrite1040:)}[/tex]

find the volume of each figure. Round to the nearest tenth if necessary.​

Answers

Answer:

1385.4

Step-by-step explanation:

Volume=pi*r^2*h=pi*49*9=1385.4

Can someone PLEASE answer the Algebra Question CORRECTLY BELOW!
Thank you, I will mark brainiest!

Answers

Answer:

There are 0.454 kg in one pound.

So, in 120 pounds there are 0.454 x 120 kgs.

This is equal to 54.48, and the answer is 54.48 kg.

Let me know if this helps!

Inverse proportion
fourteen people could paint 35 identical plates in 2 hours
At this rate, how long would it take 20 people to paint 60 identical plates?
I know answer I just need explanati
:]

Answers

Answer:

let the number of plate be n,rate be r and number of people be p

P=K(constant)/(n*t)

K=PNT

K=14*35*2

K=980

T=(K)/(PN)

T=980/(20*60)

T=980/1200

T=0.817 hours=49 minutes.

what is 10 5/8 - 8 2/7

Answers

Answer:

2 19/56 is the answer.

Step-by-step explanation:

10 5/8 - 8 2/7

or, 85/8 - 58/7

or, (595-464)/56

or, 131/56

= 2 19/56

1. Find the measure of angle R.

Answers

Answer:

the first option 40 degrees

Step-by-step explanation:

the outward angle at the center of the circle between the two tangential points is 220 degrees.

that means that the inward angle between them is

360 - 220 = 140 degrees.

now consider that there is a triangle between the center of the circle, one of the tangential points (it does not matter which one, as the upper and the lower triangles are equal) and the point R.

we know the angle at the tangential point : 90 degrees by definition (otherwise it would not be a tangent).

and we know the angle at center of the circle, which is half of the inward angle

140 / 2 = 70 degrees.

and at point R we have half of the full angle R.

we can calculate that half by using the fact that the sum of all angles in a triangle is always 180 degrees.

180 = 90 + 70 + R/2

180 = 160 + R/2

20 = R/2

R = 40 degrees

Find the area of the shaded regions:

Answers

Answer:

18[tex]\pi[/tex]

[tex]\frac{80}{360} * 81 \pi[/tex]

Step-by-step explanation:

MATCH THE SYSTEM OF EQUATIONS ON THE LEFT WITH THE APPROPRIATE SOLUTION ON THE RIGHT

Answers

Answer:

Step-by-step explanation:

Best answer gets brainliest and 5 star

Answers

Answer:

d no.

Step-by-step explanation:

because in my my personal opinion the function shown on the graph has a smaller rate of change, but a higher starting point

The answer is A. Calculating the rate of change for the graph is 3 and that of the equation is 4. The starting point of the graph is -2 and that of the equation is 6.

I need help please slope

Answers

Answer:

Step-by-step explanation:

The formula for slope is y2-y1/x2-x1 where y2 and x2 are the x and y coordinates from a coordinate pair and y1 and x1 are the coordinates from another coordinate pair. In this case, 2 coordinate pairs are given: (30,75) and (10, 35)  75-35/30-10 would be your slope, or, 40/20, or simplified, 2.

Your slope is 2

in what interval is the function f(x)=squareroot x^2+5x+4 defined

Answers

9514 1404 393

Answer:

  (-∞, -4] U [-1, ∞)

Step-by-step explanation:

The quadratic expression factors as ...

  x^2 +5x +4 = (x +4)(x +1)

The zeros of this expression are where these factors are zero, at x=-4 and x=-1. The product is negative when one factor is negative and the other is positive, in the region -4 < x < -1. It is non-negative elsewhere. f(x) is defined where the quadratic is not negative, on the union of intervals ...

  (-∞, -4] U [-1, ∞)

Answer:

-4 <= x >= -1

Step-by-step explanation:

Find where x^2+5x+4 < 0, negative sq roots are imagingary numbers.

So factor

(x + 4) (x + 1) = 0

x = -4 and x = -1

so x must be <= -4 or x >= -1

the interval is

-4 <= x >= -1

1+1=

please help me, this question is very difficult​

Answers

I think it’s 47743774367

Answer:

2 or tricky answer 11

Which could be the graph of f(x) = |x - h| + k if h and k are both positive?

Answers

Answer:

The first option would be your answer. The graph should be positive due to the modulus.

The first option is good.

Hope it helped!

Step-by-step explanation:

Answer:

A

Step-by-step explanation:

SOMEONE PLEASE HELP ME
Sandra is choosing an Internet service provider.
• Smart Dot Company costs $12 per month plus $0.50 for each hour of Internet used.
• Communication Plus costs $2.50 for every hour of Internet used.
a. Create an equation to represent the cost of using the internet with each company. (2 marks) Let C represent the cost of using internet in any month.
Let t represent the number of hours used

Answers

Smart Dot, multiply the cost per hour by number of hours (t) and add to the monthly fee:

C = 0.50t + 12

Communication plus: Multiply the cost per hour by number of hours (t)

C = 2.50t

please help asap!!! i dont understand it

Answers

Answer:

a

Step-by-step explanation:

A perpendicular bisector, intersects a line at its mid point and is perpendicular to it.

Calculate slope m using the slope formula

m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]

with (x₁, y₁ ) = (- 7, 1) and (x₂, y₂ ) = (9, 13)

m = [tex]\frac{13-1}{9-(-7)}[/tex] = [tex]\frac{12}{9+7}[/tex] = [tex]\frac{12}{16}[/tex] = [tex]\frac{3}{4}[/tex]

Given a line with slope m then the slope of a line perpendicular to it is

[tex]m_{perpendicular}[/tex] = - [tex]\frac{1}{m}[/tex] = - [tex]\frac{1}{\frac{3}{4} }[/tex] = - [tex]\frac{4}{3}[/tex] ←  slope of perpendicular bisector

Given endpoints (x₁, y₁ ) and (x₂, y₂ ) then the midpoint is

([tex]\frac{x_{1}+x_{2} }{2}[/tex], [tex]\frac{y_{1}+y_{2} }{2}[/tex] )

using (x₁, y₁ ) = (- 7, 1) and (x₂, y₂ ) = (9, 13) , then

midpoint = ( [tex]\frac{-7+9}{2}[/tex], [tex]\frac{1+13}{2}[/tex] ) = ( [tex]\frac{2}{2}[/tex], [tex]\frac{14}{2}[/tex] ) = (1, 7 )

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

Here m = - [tex]\frac{4}{3}[/tex] , then

y = - [tex]\frac{4}{3}[/tex] x + c ← is the partial equation

To find c substitute the midpoint (1, 7) into the partial equation

7 = - [tex]\frac{4}{3}[/tex] + c ⇒ c = [tex]\frac{21}{3}[/tex] + [tex]\frac{4}{3}[/tex] = [tex]\frac{25}{3}[/tex]

y = - [tex]\frac{4}{3}[/tex] x + [tex]\frac{25}{3}[/tex] ← equation of perpendicular bisector

f(x) = (x - 5) (2x - 7) (7x - 3) has zeros at x = -3.5, x = 3/7, and x = 5.

what is the sign of f on the interval 3/7 < x < 5 ?

1. f is always positive on the interval.
2. f is always negative on the interval.
3. f is sometimes positive and sometimes negative on the interval.

Answers

The function f(x) will be sometimes positive and sometimes negative on the interval so option (3) will be correct.

What is a function?

A certain kind of relationship called a function binds inputs to essentially one output.

In other terms, a function is a relationship between variables, and the type of relationship that exists between the variables defines the function, such as y = sinx and y = x +6.

Given function is

f(x) = (x - 5) (2x - 7) (7x - 3)

The term (x - 5) will be negative if x < 5.

The term (2x - 7) will be negative if x<3.5

Let's say if x = 4 then (x - 5) will be negative but (2x - 7) will be positive and hence overall value will be negative.

But if x = 3 then (x - 5) will be negative and (2x - 7)  will also be negative and hence overall value will be negative

Hence the function f is sometimes positive and sometimes negative on the interval.

For more about the function

brainly.com/question/23712366

#SPJ5

Answer:

always negative the other guy was wrong because when you wrote 2x - 7 you meant 2x + 7 I know this because it’s on Khan Academy

Step-by-step explanation:

What is the difference between-5 and 2

Answers

Answer:

7

Step-by-step explanation:

Going from -5 to 2 we get

1) -4

2) -3

3) -2

4) -1

5) 0

6) 1

7) 2

So, in total, there are 7 numbers between -5 and 2

if u can help be fast please​

Answers

A) 5 sides = 72.00

interior =108.00

B) 9 sides = 40.00

interior = 140.00

C) 15 sides = 24.00

interior = 156.00

D) 19 sides = 18.95

interior = 161.05

These are exterior angles right? y'know what I'll just put both

Phoebe took a survey of her classmates' favorite sport. The results are in the table below:

Answers

The relative frequency for football is the number of people who like football divided by total people:

4/28 = 0.14

Answer: 0.14

Instructions: Find the missing side. Round your answer to the nearest
tenth.
15
66°
х
x
=

Answers

Answer:

x = 16.4

Step-by-step explanation:

Since this is a right triangle, we can use trig functions

sin theta = opp / hyp

sin 66 = 15/x

x sin 66 = 15

x = 15/sin 66

x=16.41954

Rounding to the nearest tenth

x = 16.4

please answer fast urgently ​

Answers

Answer:

{1,2,3,4,5,6}

.

.

.

.

1/3

correct answer

Answer:

1,2,3,4,5,6

1/3

the correct ans

When a new cellphone is put on the market, the demand each month can be described by the function C of t is equal to negative square root of the quantity t squared plus 4 times t minus 12 end quantity plus 3 where C (t) represents the demand of the cellphone (measured in millions of people) and the time, t, is measured in months. Which of the following solution(s) are valid for a positive demand? (7, 0) and (3, 0) (–6, 3) and (2, 3) (6, 3) (2, 3)

Answers

Answer:

(2, 3)

Step-by-step explanation:

Answer:

It is (2,3)

Step-by-step explanation:

HELP ILL GIVE U BRAINLIEST

Answers

Answer:

-6 33/40

Step-by-step explanation:

[tex]2\frac{5}{8} = 2.625\\-2\frac{3}{5} = 2.6\\\\2.625 *-2.6 = -6.825\\\\-6.825 = -6\frac{33}{40}[/tex]

5x2y and 7xy2 are like terms.

True
False

Answers

Answer: False

The variable portions x^2y and xy^2 are slightly different, so that's why we don't have like terms here.

Answer:

False

Step-by-step explanation:

Like terms are those terms where they have the same variable

so here

5x2y variables are = 5x and 2y

7xy2 variables are = 7x and y2

you can observe that x variable is same but y variable is not same as 5x3y have 2y whereas 7xy2 have y2#

so the answer is FALSE

The display provided from technology available below results from using data for a smartphone carrier's data speeds at airports to test the claim that they are from a population having a mean less than 6.00 Mbps. Conduct the hypothesis test using these results. Use a 0.05 significance level. Identify the null and alternative hypotheses, test statistic, P-value, and state the final conclusion that addresses the original claim. What are the null and alternative hypotheses?


T-Test


μ<4.00


t=-3.033077


p=0.002025


x=3.48


Sx=1.150075


n=45

Answers

Answer:

Kindly check explanation

Step-by-step explanation:

Given the T test output :

T-Test

μ<4.00

t=-3.033077

p=0.002025

x=3.48

Sx=1.150075

n=45

Given that population mean, μ = 6

Confidence level, α = 0.05

The hypothesis :

H0 : μ = 6.00

H1 : μ < 6.00

From the t test output given :

The test statistic :

T = -3.033077

T = - 3.03 (2 decimal places)

The Pvalue :

P = 0.002025

Pvalue = 0.002 (3 decimal places)

The conclusion :

Decision region ; Reject H0 : if Pvalue < α

Since ; Pvalue < α

Reject H0 ; There is sufficient evidence to support claim that sample is from a population with a mean less than 6.

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