Answer:
The probability that at lest one job will be missed in 57 second is
=0.819134
Step-by-step explanation:
Poisson distribution:
A discrete random variable X having the enumerable set {0,1,2,....} as the spectrum, is said to be Poisson distribution.
for x=0,1,2...
λ is the average per unit time
Given that, a job arrives at a web server with the probability 0.03.
Here λ=0.03, t=57 second.
The probability that at lest one job will be missed in 57 second is
=P(X≥1)
=1- P(X<1)
=1- P(X=0)


=0.819134
Let's say this number is a:
a*(a-9) = 90
a^2-9a-90 = 0
(a-15)(a+6) = 0
a = 15 or a = -6
Therefor a. would be the correct answer :)