18. The servicing of a machine requires two separate steps, with the time needed for the first step being an exponential random variable with mean 0.2 hour and the time for the
second step being an independent exponential random variable with mean 0.3 hour. If a
repair person has 20 machines to service, what is approximately the probability that all the
work can be completed in 8 hours?

Step-by-step explanation:

Let X denote the first step

Let Y denote the second step

Then

E(X) = 0.2

E (Y) = 0.3

V (X) = 0.04

V (Y) = 0.09

Now,

E(X,Y) = E[X] + E{Y}

0.2 + 0.3 = 0.5

And since X and Y are independent

Therefore,

V(X , Y) = V(X) + V(Y)

= 0.04 + 0.09

= 0.13

Now required probability is

= Φ(-1.24)

= 1 - Φ (1.24)

= 1 - 0.8925

= 0.1075

o= 4(i) +3

step-by-step explanation:

o is your output value and i is your input value. so, for example, if we stuck 7 in as our input, we would first multiply by 4 ( pemdas ), which equals 28. then we would add 3 to 28, for a total output of 31. this may not be a graph, but, it is a way to solve your formula..

the answer would be 1 1/72

step-by-step explanation:

you can rewrite the equation by separating the parts and then solving individually:

10-9=1

1/8 - 1/9=

find l c d and then combine:

1 1/72