First we have to find out how much he makes in a day aside from what he makes a day aside from his deliveries, so 9 x 8 = 72. Then we take 155 - 72 = 83. Then since he wants to make more than 155, we'll add one to 83, then take that divided by 6. 84/6=14. So he'd have to make at least 14 deliveries to make $156 in a day.
