well if he works for one week or 5 days every day as a cashier he works 4 hours for 4$ which means he will make 16$ everyday as a cashier. as being a waiter he works 3 hours a day for 5.50$ each hour so $5.50*3= $16.5. add 16.5 and 16 to get 32.5 is how much he makes a day. so for how many days he works multiply that by 32.5 so if he works for 1 week (5 days) he will make $162.5 every week or (5 days)
sorry for the long answer comment if you have questions
