: Customers arrive at a shopping mart randomly at a rate of 7 per hour. a) Find the probability that during any 90 minutes’ period, the number of customers arriving at the shopping mart is exactly 8
b) If a customer arrives at 11.30 am, find the probability that the next patient arrives before
11.45 am.

The question is kind of confusing. if it's asking how many variations of answers can you give. then do 4^5 for your answer.this would be something like the first question could be a and the 2nd c or first b next c etc. if you can, ask the teacher for a better confirmation of what it's asking. if i'm assuming correctly what it's asking, it's 625 different variations.