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Amanda [17]
2 years ago
13

Kieran’s wallet contains 7 bills: three $5 bills, two $10 bills, one $20 bill, and one $100 bill. If Kieran pulls out two bills

at random, what is the probability that he selects exactly two $5 bills? Use complete sentences to explain the probability. In your final answer, include all of your calculations.
Mathematics
2 answers:
Aleksandr-060686 [28]2 years ago
7 0

Answer:

1/7

Step-by-step explanation:

$5 = 3, $10= 2, $20= 1, $100= 1- total 7 bills

  • Probability of getting $5 bill is 3/7
  • Probability of getting second $5 bill is 2/6= 1/3 as one of $5 bill already taken and total number of bills reduced to 6
  • Probability of getting 2 of $5 bills is the product of individual probabilities: 3/7*1/3= 1/7

Answer is 1/7

notka56 [123]2 years ago
6 0

Answer:

Exact probability = 1/7

(Approximate probability = 0.142857)

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

Explanation:

There are three 5 dollar bills out of 7 total. The probability of selecting a five dollar bill is 3/7. Let A = 3/7 since we'll use it later.

After the first selection is made, we have 3-1 = 2 five dollar bills left out of 7-1 = 6 bills overall. This is assuming we do not put the first selection back, or replace it with another five dollar bill.

The probability of selecting another five dollar bill is 2/6 = 1/3. Let B = 1/3.

Multiply the values of A and B to get

A*B = (3/7)*(1/3) = (3*1)/(7*3)= 1/7

Note the 3's divide and cancel out.

Using a calculator, 1/7 = 0.142857 approximately

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I believe the answer is 3/8. The whole portion of employees, which is translated as 8/8 is deducted by 5/8, which is the population of male employees.
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Draw the unit circle with center (0,0)and plot the point P=(6,2). Observe there are TWO lines tangent to the circle passing thro
scZoUnD [109]

Answer:

Step-by-step explanation:

Given that a tangent is drawn from P (6,2) to unit circle with center at the origin.

The tangent passing through (6,2) would have equaiton of the form

y-6 = m(x-2)\\y =mx-2m+6 for suitable m.

Because this line is tangent, distance of centre of circle namely origin is the radius 1.

i.e. |\frac{-2m+6}{\sqrt{1+m^2} } |=1\\(-2m+6 )^2 = 1+m^2\\3m^2-24m+35=0\\\\m=1.918, 6.082

the coordinates are the intersection of the tangent with the circle

They are (-0.162, 0.987) and (0.462,-0.887)

8 0
2 years ago
On Wednesday, Danielle skated 2/3 of the way around the track in 2 minutes. Her younger brother skated 3/4 of Danielle's distanc
katen-ka-za [31]
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4 0
2 years ago
Sean has 15,000 to invest she will put some of it into a fund that pays 4.5% annual interest in the rest in a certificate of dep
DENIUS [597]

Answer:$12500 was invested into the account that pays 4.5% annual interest..

$2500 was invested into the the certificate of deposit that pays 1.8% annual interest..

Step-by-step explanation:

Let x represent the amount invested into the account that pays 4.5% annual interest.

Let y represent the amount invested into the certificate of deposit that pays 1.8% annual interest.

Sean has 15,000 to invest. She will put some of it into a fund that pays 4.5% annual interest and the rest in a certificate of deposit that pays 1.8% annual interest. This means that

x = y + 15000

The formula for simple interest is expressed as

I = PRT/100

Where

P represents the principal

R represents interest rate

T represents time in years

I = interest after t years

Considering the account earning 4.5% interest, the interest would be

I = (x × 4.5 × 1)/100 = 0.045x

Considering the account earning 11% interest, the interest would be

I = (x × 1.8 × 1)/100 = 0.018y

if she wants to earn 4.05% annual interest on the total amount, the amount would be

4.05/100 × 15000 = 607.5

Therefore,

0.045x + 0.018y = 607.5 - - - - - - - - - - -1

Substituting x = 15000 - y into equation 1, it becomes

0.045(15000 - y) + 0.018y = 607.5

675 - 0.045y + 0.018y = 607.5

- 0.045y + 0.018y = 607.5 - 675

- 0.027y = - 67.5

y = - 67.5/- 0.027

y = $2500

x = 15000 - y = 15000 - 2500

x = $12500

6 0
2 years ago
One of your peers claims that boys do better in math classes than girls. Together you run two independent simple random samples
JulijaS [17]

Answer:

Step-by-step explanation:

Hello!

To test if boys are better in math classes than girls two random samples were taken:

Sample 1

X₁: score of a boy in calculus

n₁= 15

X[bar]₁= 82.3%

S₁= 5.6%

Sample 2

X₂: Score in the calculus of a girl

n₂= 12

X[bar]₂= 81.2%

S₂= 6.7%

To estimate per CI the difference between the mean percentage that boys obtained in calculus and the mean percentage that girls obtained in calculus, you need that both variables of interest come from normal populations.

To be able to use a pooled variance t-test you have to also assume that the population variances, although unknown, are equal.

Then you can calculate the interval as:

[(X[bar]_1-X[bar_2) ± t_{n_1+n_2-2;1-\alpha /2} * Sa*\sqrt{\frac{1}{n_1} +\frac{1}{n_2} }]

Sa= \sqrt{\frac{(n_1-1)S^2_1+(n_2-1)S^2_2}{n_1+n_2-2} } = \sqrt{\frac{14*(5.6^2)+11*(6.7^2)}{15+12-2} }= 6.108= 6.11

t_{n_1+n_2-2;1-\alpha /2}= t_{15+12-2;1-0.05}= t_{25;0.95}= 1.708

[(82.3-81.2) ± 1.708* (6.11*\sqrt{\frac{1}{15}+\frac{1}{12}  }]

[-2.94; 5.14]

Using a 90% confidence level you'd expect the interval [-2.94; 5.14] to contain the true value of the difference between the average percentage obtained in calculus by boys and the average percentage obtained in calculus by girls.

I hope this helps!

3 0
2 years ago
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