(2.5+3)X=22

5.5X =22

5.5 times %5.5 =22%5.5

X =4

There are 4 books in each series.

2

Solution: Suppose it can be transported x times next time.

5(X+3)=35

5(X+3)%5=35%5

X+3=7

X+3-3=7-3

X=4

A: It can be delivered four times in the afternoon.