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Allisa [31]
3 years ago
13

You are getting a line-up ready for a school kickball game. you have 77 girls and 77 boys. the rules state each child must kick

the same number of times and alternate girl-boy or boy-girl. how many ways can a line-up be made for one round of kicking?
Mathematics
1 answer:
mezya [45]3 years ago
3 0
1. Since each child kicks the same number of times, it is not important whether he or she kicks 1 time, 2, 3 or more times. So let all of them kick 1 time.

2. assume we start with a girl. We can start with either of the 77 girls, then second is a boy which can be either of the 76, the third is a girl which can be either of the 76 remaining, then the forth is one of the 76 boys...

3. So starting with a girl we have

77*(77)*76*(76)*75*(75)....*2*(2)*1*(1)=77!*77!

4. OR we could have started with a boy, where we would get again 77!*77!

5. Answer: 77!*77!+77!*77!=2(77!)^{2}
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Answer:

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Step-by-step explanation:

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3 years ago
According to a Yale program on climate change communication survey, 71% of Americans think global warming is happening.† (a) For
SpyIntel [72]

Answer:

a) 0.2741 = 27.41% probability that at least 13 believe global warming is occurring

b) 0.7611 = 76.11% probability that at least 110 believe global warming is occurring

Step-by-step explanation:

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

In which C_{n,x} is the number of different combinations of x objects from a set of n elements, given by the following formula.

C_{n,x} = \frac{n!}{x!(n-x)!}

And p is the probability of X happening.

The expected value of the binomial distribution is:

E(X) = np

The standard deviation of the binomial distribution is:

\sqrt{V(X)} = \sqrt{np(1-p)}

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that \mu = E(X), \sigma = \sqrt{V(X)}.

In this problem, we have that:

p = 0.71

(a) For a sample of 16 Americans, what is the probability that at least 13 believe global warming is occurring?

Here n = 16, we want P(X \geq 13). So

P(X \geq 13) = P(X = 13) + P(X = 14) + P(X = 15) + P(X = 16)

In which

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

P(X = 13) = C_{16,13}.(0.71)^{13}.(0.29)^{3} = 0.1591

P(X = 14) = C_{16,14}.(0.71)^{14}.(0.29)^{2} = 0.0835

P(X = 15) = C_{16,15}.(0.71)^{15}.(0.29)^{1} = 0.0273

P(X = 16) = C_{16,16}.(0.71)^{16}.(0.29)^{0} = 0.0042

P(X \geq 13) = P(X = 13) + P(X = 14) + P(X = 15) + P(X = 16) = 0.1591 + 0.0835 + 0.0273 + 0.0042 = 0.2741

0.2741 = 27.41% probability that at least 13 believe global warming is occurring

(b) For a sample of 160 Americans, what is the probability that at least 110 believe global warming is occurring?

Now n = 160. So

\mu = E(X) = np = 160*0.71 = 113.6

\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{160*0.71*0.29} = 5.74

Using continuity correction, this is P(X \geq 110 - 0.5) = P(X \geq 109.5), which is 1 subtracted by the pvalue of Z when X = 109.5. So

Z = \frac{X - \mu}{\sigma}

Z = \frac{109.5 - 113.6}{5.74}

Z = -0.71

Z = -0.71 has a pvalue of 0.2389

1 - 0.2389 = 0.7611

0.7611 = 76.11% probability that at least 110 believe global warming is occurring

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2 years ago
Is 92 1/2 pounds equivalent to 1,480 ounces
kow [346]
Hi there!

Since

16 ounces = 1 pound,

We should divide 1480 by 16 and see if it equals 92.5.

1480 ÷ 16 = 92.5
92.5 = 92.5

Answer:
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Hope this helps!
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alekssr [168]
Hey there :)

- tan²x + sec²x = 1    or    1 + tan²x = sec²x

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Take tan²x to the other side {You will have the same answer}

1 = - tan²x = sec²x or sec²x - tanx = 1

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3 years ago
Convert 6 centimeters per second to miles per hour.
bearhunter [10]

Answer:

A, 0.13 mph.

Step-by-step explanation:

To get that, divide the cm/sec by 44.704.

6/44.704 ≈ 0.13

4 0
2 years ago
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