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3 years ago

Need help with this ASAP!!

Mathematics

2 answers:

postnew [5]3 years ago

7 0

Answer:

Step-by-step explanation:

40x1.6

stiks02 [169]3 years ago

3 0

Answer:

64.37376

Step-by-step explanation:

40 miles = 64.37376

Hope this helps!

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It's due tomorrow I need answers I don't know what to do

Mariulka [41]

#2 is 1 and 2 is both 78%

4 0

3 years ago

The proportion of high school seniors who are married is 0.02. Suppose we take a random sample of 300 high school seniors; a.) F

cricket20 [7]

Answer:

a) Mean 6, standard deviation 2.42

b) 10.40% probability that, in our sample of 300, we find that 8 of the seniors are married.

c) 14.85% probability that we find less than 4 of the seniors are married.

d) 99.77% probability that we find at least 1 of the seniors are married

Step-by-step explanation:

For each high school senior, there are only two possible outcomes. Either they are married, or they are not. The probability of a high school senior being married is independent from other high school seniors. 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.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

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

In this problem, we have that:

$n = 300, p = 0.02$

a.) Find the mean and standard deviation of the sample count X who are married.

Mean

$E(X) = np = 300*0.02 = 6$

Standard deviation

$\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{300*0.02*0.98} = 2.42$

b.) What is the probability that, in our sample of 300, we find that 8 of the seniors are married?

This is P(X = 8).

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

$P(X = 8) = C_{300,8}.(0.02)^{8}.(0.98)^{292} = 0.1040$

10.40% probability that, in our sample of 300, we find that 8 of the seniors are married.

c.) What is the probability that we find less than 4 of the seniors are married?

$P(X < 4) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3)$

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

$P(X = 0) = C_{300,0}.(0.02)^{0}.(0.98)^{300} = 0.0023$

$P(X = 1) = C_{300,1}.(0.02)^{1}.(0.98)^{299} = 0.0143$

$P(X = 2) = C_{300,2}.(0.02)^{2}.(0.98)^{298} = 0.0436$

$P(X = 3) = C_{300,3}.(0.02)^{3}.(0.98)^{297} = 0.0883$

$P(X < 4) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) = 0.0023 + 0.0143 + 0.0436 + 0.0883 = 0.1485$

14.85% probability that we find less than 4 of the seniors are married.

d.) What is the probability that we find at least 1 of the seniors are married?

Either no seniors are married, or at least 1 one is. The sum of the probabilities of these events is decimal 1. So

$P(X = 0) + P(X \geq 1) = 1$

From c), we have that $P(X = 0) = 0.0023$ . So

$0.0023 + P(X \geq 1) = 1$

$P(X \geq 1) = 0.9977$

99.77% probability that we find at least 1 of the seniors are married

3 0

3 years ago

What two numbers multiply to -72, adds up to -1

valkas [14]

They are -9 and 8. because since 9 times 8 is 72, you need the 9 to be negative to add to -1

8 0

3 years ago

Which of the following is equivalent to (x+4)(3x^2+2x)?

Mrrafil [7]

We can multiple this binomial and this trinomial to find an equivalent expression.

(x + 4)(3x^2 + 2x)

3x^3 + 2x^2 + 12x^2 + 8x

Combine like terms.

3x^3 + 14x^2 + 8x is the equivalent polynomial.

7 0

3 years ago

Can a triangle have sides with the given lengths 1ft,5ft,11ft

Scilla [17]

Let a,b and c is side of a triangle where:
a = 1
b = 5
c = 11

a^2 + b^2 = c^2. if the following statement is right, then triangle have these side.

1^2 + 5^2 = 11^2
1 + 25 = 121
26 != 121 ( != means not equal to)

Therefore, triangle can't have side length of 1, 5 and 11 ft.

3 0

3 years ago