Suppose you are given 4 food stamps. You are allowed to vitit the grocery store between 1 and 50 times per day where each day are independent. Everytime, you visit a grocery store, you must use a food stamp. a) find probability you use all food stamps within 8 days. b) how many days do you expected to use the last food stamp. c) In term of mean and standard deviation, is there a chance you use your last food stamp on day 999?