Help QuickTime I got minus 10 but apparently its wrong

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

This is different from the first one can someone me

Suppose a store sells an average of 80 cases of soda per day. assume that each case contains 24 cans of soda and that the store is open 10 hours per day. find the average number of soda that the store sells per hour.