-3 + { 1 – 3[20 + 2(-6

The Perimeter of the park is 318 m. Determine the length of the park<br><br> PLEASE HELP!!!!!!!!!

Vadim26 [7]

Answer:

79.5m

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

The probability that your call to a service line is answered in less than 30 seconds is 0.75. Assume that your calls are indepen

vfiekz [6]

Answer:

a) 0.2581

b) 0.4148

c) 17

Step-by-step explanation:

For each call, there are only two possible outcomes. Either they are answered in less than 30 seconds. Or they are not. The probabilities for each call are independent. So we use the binomial probability distribution to solve this question.

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.

In this problem we have that:

$p = 0.75$

a. If you call 12 times, what is the probability that exactly 9 of your calls are answered within 30 seconds? Round your answer to four decimal places (e.g. 98.7654).

This is $P(X = 9)$ when $n = 12$ . So

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

$P(X = 9) = C_{12,9}.(0.75)^{9}.(0.25)^{3} = 0.2581$

b. If you call 20 times, what is the probability that at least 16 calls are answered in less than 30 seconds? Round your answer to four decimal places (e.g. 98.7654).

This is $P(X \geq 16)$ when $n = 20$

So

$P(X \geq 16) = P(X = 16) + P(X = 17) + P(X = 18) + P(X = 19) + P(X = 20)$

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

$P(X = 16) = C_{20,16}.(0.75)^{16}.(0.25)^{4} = 0.1897$

$P(X = 17) = C_{20,17}.(0.75)^{17}.(0.25)^{3} = 0.1339$

$P(X = 18) = C_{20,18}.(0.75)^{18}.(0.25)^{2} = 0.0669$

$P(X = 19) = C_{20,19}.(0.75)^{19}.(0.25)^{1} = 0.0211$

$P(X = 20) = C_{20,20}.(0.75)^{20}.(0.25)^{0} = 0.0032$

So

$P(X \geq 16) = P(X = 16) + P(X = 17) + P(X = 18) + P(X = 19) + P(X = 20) = 0.1897 + 0.1339 + 0.0669 + 0.0211 + 0.0032 = 0.4148$

c. If you call 22 times, what is the mean number of calls that are answered in less than 30 seconds? Round your answer to the nearest integer.

The expected value of the binomial distribution is:

$E(X) = np$

In this question, we have $n = 22$

So

$E(X) = 22*0.75 = 16.5$

The closest integer to 16.5 is 17.

7 0

3 years ago

If there are 400 cubic centimeters of a chemical in 1 liter of solution, how many cubic centimeters of water must be added to di

mars1129 [50]

$1l=1dm^3\\1dm=10cm\to1dm^3=(10cm)^3=1000cm^3\\\\1l=1000cm^3\\-------------\\ \begin{array}{ccc}400cm^3&-&25\%\\1000cm^3+x&-&100\%\end{array}\\cross\ multiply\\25(1000+x)=400\times100\\25000+25x=40000\ \ \ \ \ |subtract\ 25000\ from\ both\ sides\\25x=15000\ \ \ \ |divide\ both\ sides\ by\ 25\\\boxed{x=600\ (cm^3)}\\\\Answer:Must\ be\ added\ 600cm^3\ of\ water.$

5 0

3 years ago

2 questions here. What does the equation of line mean on number 7? And how do I do 8?

ycow [4]

Equation of line is doubling

6 0

3 years ago

I need help with four questions NOW!!!! please.

TiliK225 [7]

1- Formal
2- Something familiar, and something he has strong feelings about.
3- a question
4- Brainstorming

Hope this helps! : )

4 0

3 years ago

-3 + { 1 – 3[20 + 2(-6 – 7)]}