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3 years ago

A chorus has 5 girls and 15 boys. If two are chosen at random to sing a duet, what is the probability that both will be boys?

Mathematics

2 answers:

Sonbull [250]3 years ago

8 0

Answer:

Step-by-step explanation:

If you ad them together you get 20 15/20 are boys 15 divided by 20 is .75

Galina-37 [17]3 years ago

8 0

.75 or 75%

If there’s 20 kids total in the class and 15 out of the 20 are boys then you would divide the 15 by 20 and get .75 if you were doing it for girls then you would divide 5 by 20 and you would get .25 or 25%

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ANSWER ASAP GIVING BRAILIEST AND STUFF!

MrRissso [65]

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3 years ago

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A random variable X follows the uniform distribution with a lower limit of 670 and an upper limit of 750.a. Calculate the mean a

DENIUS [597]

You can compute both the mean and second moment directly using the density function; in this case, it's

$f_X(x)=\begin{cases}\frac1{750-670}=\frac1{80}&\text{for }670\le x\le750\\0&\text{otherwise}\end{cases}$

Then the mean (first moment) is

$E[X]=\displaystyle\int_{-\infty}^\infty x\,f_X(x)\,\mathrm dx=\frac1{80}\int_{670}^{750}x\,\mathrm dx=710$

and the second moment is

$E[X^2]=\displaystyle\int_{-\infty}^\infty x^2\,f_X(x)\,\mathrm dx=\frac1{80}\int_{670}^{750}x^2\,\mathrm dx=\frac{1,513,900}3$

The second moment is useful in finding the variance, which is given by

$V[X]=E[(X-E[X])^2]=E[X^2]-E[X]^2=\dfrac{1,513,900}3-710^2=\dfrac{1600}3$

You get the standard deviation by taking the square root of the variance, and so

$\sqrt{V[X]}=\sqrt{\dfrac{1600}3}\approx23.09$

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3 years ago

WILL GIVE BRAINLIEST write an equation for the nth term of the arithmetic sequence and find the 30th term 28, 25, 22, 19, ... (s

ryzh [129]

Answer: 31 - 3n

Step-by-step explanation:

step one:

25 - 28 = -3

22 - 25 = -3

19 - 22 = -3

d = -3

Step two:

An = a1 + (n-1) d

= 28 + (n-1) -3

= 28 - 3n + 3

= 31 - 3n

a1= 28 d = 3

6 0

3 years ago

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Okay the answer for this

zepelin [54]

Your answer is d, you can not use 6 and the equation be right.

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3 years ago

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Renee, Susan, and Martha will share the cost to rent a vacation house for a week. • Renee will pay 40% of the cost. • Susan will

olga nikolaevna [1]

Answer:

Martha is wrong.

Step-by-step explanation:

Let the cost of the house is C.

Payment by Ranee = 40% of the cost

=40% of C

= $\frac{40}{100}\times C$

=0.40 C

Payment by Susan = 0.35 of the cost

=0.35 C

Combined payment by Ranee and Susan = 0.40C + 0.35C=0.75C

The remaining payment will be done by Martha.

So, the remaining payment = C- 0.75C=0.25 C

Hence, Martha will have to pay 0.25 of the cost or 25% of the cost.

So, Martha is wrong.

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3 years ago