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3 years ago

X2−10x+29=5

Mathematics

1 answer:

Irina18 [472]3 years ago

7 0

Answer:

(x-6)(x-4) = 0

Step-by-step explanation:

Subtract 5 from both sides to make the equation equal to 0. You will get the equation x2-10x+24=0. Now think of two numbers that multiply to get 24 but add to get -10. These numbers are -6 and -4. The factors of x2 are x and x which multiply to get x2. Now put two linear factors into parathesis to get (x-6)(x-4) = 0.

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Refer to Exercise 3.122. If it takes approximately ten minutes to serve each customer, find the mean and variance of the total s

garri49 [273]

Answer

a. The expected total service time for customers = 70 minutes

b. The variance for the total service time = 700 minutes

c. It is not likely that the total service time will exceed 2.5 hours

Step-by-step explanation:

This question is incomplete. I will give the complete version below and proceed with my solution.

Refer to Exercise 3.122. If it takes approximately ten minutes to serve each customer, find the mean and variance of the total service time for customers arriving during a 1-hour period. (Assume that a sufficient number of servers are available so that no customer must wait for service.) Is it likely that the total service time will exceed 2.5 hours?

Reference

Customers arrive at a checkout counter in a department store according to a Poisson distribution at an average of seven per hour.

From the information supplied, we denote that

$X=$ Customers that arrive within the hour

and since $X$ follows a Poisson distribution with mean $\alpha$ = 7

Therefore,

$E(X)= 7$

$& V(X)=7$

Let $Y =$ the total service time for customers arriving during the 1 hour period.

Now, since it takes approximately ten minutes to serve each customer,

$Y=10X$

For a random variable $X$ and a constant $c$ ,

$E(cX)=cE(X)\\V(cX)=c^2V(X)$

Thus,

$E(Y)=E(10X)=10E(X)=10*7=70\\V(Y)=V(10X)=100V(X)=100*7=700$

Therefore the expected total service time for customers = 70 minutes

and the variance for serving time = 700 minutes

Also, the probability of the distribution $Y$ is,

$p_Y(y)=p_x(\frac{y}{10} )\frac{dx}{dy} =\frac{\alpha^{\frac{y}{10} } }{(\frac{y}{10})! }e^{-\alpha } \frac{1}{10}\\ =\frac{7^{\frac{y}{10} } }{(\frac{y}{10})! }e^{-7 } \frac{1}{10}$

So the probability that the total service time exceeds 2.5 hrs or 150 minutes is,

$P(Y>150)=\sum^{\infty}_{k=150} {p_Y} (k) =\sum^{\infty}_{k=150} \frac{7^{\frac{k}{10} }}{(\frac{k}{10})! }.e^{-7} .\frac{1}{10} \\=\frac{7^{\frac{150}{10} }}{(\frac{150}{10})! } .e^{-7}.\frac{1}{10} =0.002$

0.002 is small enough, and the function $\frac{7^{\frac{k}{10} }}{(\frac{k}{10} )!} .e^{-7}.\frac{1}{10}$ gets even smaller when $k$ increases. Hence the probability that the total service time exceeds 2.5 hours is not likely to happen.

3 0

2 years ago

What is the area of this trapezoid? Enter your answer in the box.

ANEK [815]

Step-by-step explanation:

a=7+3+7=17

b=3

h=8

area=(1/2)(17+3)(8)=80

5 0

2 years ago

Read 2 more answers

Help me please and thank you

Kisachek [45]

Answer:

12.5 un^2

Step-by-step explanation:

The formula for area of a trapezoid is (a+b)/2 *h

a and b are the shorter and longer bases respectively. H is height, you have both.

Simply plug it into the equation and find your answer.

(2.5+7.5)/2 *2.5 = 5*2.5 which is equal to 12.5. Add units.

8 0

3 years ago

What is 4 divide 120 Show me that divide by 120

Lena [83]

Answer: 120 divided by 4 = 30

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

a bowl of grapes has a total massif 265 grams. the bowl has a mass of 121 grams. what is the mass of the grapes

sveticcg [70]

Answer:

144 grams

Step-by-step explanation:

the total mass of the bowl of grapes includes the bowl. to get the mass of the grapes, we need to subtract the mass of the bowl. 265 grams - 121 grams is 144 grams.

7 0

2 years ago