1. The bank counter at Universitas Islam Indonesia will give the service to 0, 1, 2, 3, 4, or 5 or more students during a certain 15-minutes period are 0.03, 0.18, 0.24, 0.28, 0.10, and 0.17, respectively. Find the probability that in this 15-minute period (a) more than 2 students get the service; (b) at most 4 students get the service; (c) 4 or more students get the service 2. A manufacturer is studying the effects of cook- ing temperature, cooking time, and t type of cooking oil for making potato chips. Three different temperatures, 4 different cooking times, and different oils are to be used. (a) What is the total number of combinations to be studied? (b) How many combinations will be used for each type of oil? (c) Discuss why permutations are not an issue in this exercise. 3. A computer starts up employs two sales programmer. Programmer 1 does the work of estimating cost for 70% of an app built by the company. Programmer 2 does the work for 30% of an app built by the company. It is known that the error rate for programmer 1 is such that 0.02 is the probability of an error when he does the work, whereas the probability of an error in the work of programmer 2 is 0.04. Suppose an app arrives and a serious error occurs in estimating cost. Which programmer would you guess did the work? Explain and show all work. 4. A computer store produces and sells cell-phone and tab. Based on long-range sales, the probability that a customer will purchase cell-phone is 0.75. Of those that purchase cell-phone, 60% also purchase earphone. But only 30% of tab buyers purchase earphone. A randomly selected buyer purchases an earphone and electronic device. What is the probability that the electronic device is cell-phone?