Question

Consider single-server Q with LIFO (last-infirst-out) services. Suppose that three customers show up at times 5, 6, and 8, and that they all have service times of 4. When does customer 2 leave the system?
a. 3
b. 9
c. 13
d. 17
e. 19a

Answer 1

Answer:

d. 17

Explanation:

The computation is shown below;

Here the time started i.e. t=0

Therefore there was no customer upto t=5 hour

At t=5

The client first came and as there was no other customer available so we begins service to customer 1

Now  

As service off is 4 hour so service to client 1 will end at

t=9 hour.

Also mid-time at t = 6

That means the client 2 came and at t = 8 the  client 3 came.

Now at t = 9 the service begins for client 3 and end at t = 13 ( 9 + 4)

At t=13 hour, so after four hours it should be 17