Write an expression for the sequence of operations described below.

A rectangle's length is 6 units greater than its width. write an equation expressing the rectangle's area, a, as a function of w

vladimir1956 [14]

Let the width be w

Width = w
Length = w + 6
Area = a

a = w(w + 6)
a = w² + 6w

Answer: a = w² + 6w

7 0

3 years ago

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A commuter must pass through 5 traffic lights on her way to work and will have to stop at each one that is red. She estimates th

sergij07 [2.7K]

Answer:

(a) The mean or expected value of X is 2.2.

(b) The standard deviation of X is 1.3.

Step-by-step explanation:

Let X = number of times the traffic light is red when a commuter passes through the traffic lights.

The probability distribution of X id provided.

The formula to compute the mean or expected value of X is:

$\mu=E(X)=\sum x.P(X=x)$

The formula to compute the standard deviation of X is:

$\sigma=\sqrt{E(X^{2})-(E(X))^{2}}$

The formula of E (X²) is:

$E(X^{2})=\sum x^{2}.P(X=x)$

(a)

Compute the expected value of X as follows:

$E(X)=\sum x.P(X=x)\\=(0\times0.06)+(1\times0.25)+(2\times0.35)+(3\times0.15)+(4\times0.13)+(5\times0.06)\\=2.22\\\approx2.2$

Thus, the mean or expected value of X is 2.2.

(b)

Compute the value of E (X²) as follows:

$E(X^{2})=\sum x^{2}.P(X=x)\\=(0^{2}\times0.06)+(1^{2}\times0.25)+(2^{2}\times0.35)+(3^{2}\times0.15)+(4^{2}\times0.13)+(5^{2}\times0.06)\\=6.58$

Compute the standard deviation of X as follows:

$\sigma=\sqrt{E(X^{2})-(E(X))^{2}}\\=\sqrt{6.58-(2.22)^{2}}\\=\sqrt{1.6516}\\=1.285\\\approx1.3$

Thus, the standard deviation of X is 1.3.

4 0

3 years ago

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Suppose that on the average, 7 students enrolled in a small liberal arts college have their automobiles stolen during the semest

strojnjashka [21]

Answer:0.9991

Step-by-step explanation:

The Poisson distribution probability formula is given by :-

$P(X=x)=\dfrac{e^{-\lambda}\lambda^x}{x!}$ , where \lambda is the mean of the distribution and x is the number of success

Given : $\lambda=7$

The probability that more than 1 student will have his automobile stolen during the current semester is given by :-

$P(x\geq1)=1-P(x=0)=1-(\dfrac{e^{-7}7^0}{0!})\\\\=1-e^{-7}=0.99908811\approx0.9991$

Hence, the probability that more than 1 student will have his automobile stolen during the current semester =0.9991

3 0

3 years ago

On Friday, a local hamburger shop sold a combined total 312 of hamburgers and cheeseburgers. The number of cheeseburgers sold wa

Rainbow [258]

Answer:

total number of hamburger =312

total number of cheeseburger=2x312

=624

Step-by-step explanation:

the answer is 624

8 0

3 years ago

A store has 80 modems in its inventory, 30 coming from source a and the remainder from source

Mrrafil [7]

The number of defective modems in the inventory is 20%⋅ 30 + 8%⋅ 50 = 10 (out of 80). Note that the number of defectives in the inventory is fixed, i.e., we are not told that there is 1 8 probability that a modem in the inventory is defective, but rather that exactly 1 8 of all modems are defective. The probability that exactly two modems in a random sample of five are defective is = 0.102

5 0

2 years ago