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3 years ago

What times blank equal 90 and a 100

Mathematics

2 answers:

torisob [31]3 years ago

4 0

Answer:

10x9=90

10x10=100

Step-by-step explanation:

satela [25.4K]3 years ago

3 0

Answer:

35 is a factor of 90 so yes 35.

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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

3 years ago

What is the sum of the geometric series 2^0 + 2^1 + 2^2 + 2^3 + 2^3 + 2^4 + … + 2^9?

GREYUIT [131]

Sum is
$S_{n}=\frac{a_{1}(1-r^{n})}{1-r}$

r=common ratio
a1=first term
it looks like 2^0=1 is the first term aka a1
it goes to the 9th term (2^9)

sub
$S_{9}=\frac{1(1-(2)^{9})}{1-2}$
$S_{9}=\frac{1-512}{-1}$
$S_{9}=\frac{-511}{-1}$
$S_{9}=511$

4 0

3 years ago

Read 2 more answers

Perform the following division:

timofeeve [1]

(33/4) / (2/8)
when dividing with fractions, flip what u r dividing by, then multiply
33/4 * 8/2 = 66/2 = 33...hmm...not an answer choice

let me try something..
(3 3/4) / (2/8) =
15/4 * 8/2 =
30/2 =
15 <====possibly this one if ur problem is : (3 3/4) / (2/8)

5 0

3 years ago

Read 2 more answers

I need help fast please!!!!!

Inessa05 [86]

Answer:

255.7 cm²

Step-by-step explanation:

A = 10²(3.14) = 314

(293/360)(314) = 255.7 cm²

8 0

3 years ago

Read 2 more answers

Please respond in detail

Serggg [28]

Answer:

No.

Step-by-step explanation:

As x increases 2^x will grow faster than 5 x^2. This is because the x in 2^x is an exponent and its graph grows very steeply compared with 5x^2 , as x increases.

For example when x = 10

5x^2 = 5*10^2 = 500

2^x = 2^10 =1024

When x = 11:

5x^2 = 605

2^x = 2048 and the difference will continue to increase.

6 0

3 years ago