
Waiting time follows an exponential distribution with mean
μ=60
μ=60 seconds. This implies λ=1μ=160λ= μ1= 601
Let X be the waiting time. for first we have to calculate the probability of customers who wait less than 30 secs.
a. X is less than 30 seconds, then we have to find ,
P(X<X1)=1āeāĪ»X1āP(X<30)=1āeāĪ»Ć0
=1āeā160Ć30 =1āeā12=1ā0.6065
=0.3935P(X<X 1)ā
P(X<30)
ā
Ā
=1āe āĪ»X 1=
1āe āĪ»Ć30 1āe ā 601Ć30 =
1āe ā 21
=1ā0.6065
=0.3935
āb. X is more than 120 seconds, then we have to find less than 120 sec
b. X is more than 120 seconds
P(X>X1)=1āP(X<X1)=1ā(1āeāĪ»X1)āP(X>120)=1ā(1āeāĪ»Ć120=eā60Ć120=eā2=0.135
P(X>X 1)āP(X>120)=1āP(X<X 1)=1ā(1āe āĪ»X 1)=1ā(1āe āĪ»Ć120= ā 601Ć120 =e ā2=0.135
To learn more about probability.
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