Adam earns $4 for every car he washes.
He gets $5 bonus for every 5 cars he washes.

1. How much will Adam earn if he washes every 5 cars?   
2. If Adam wants to earn $29, how many cars must he wash? 
3. If Adam wants to earn $75, how many cars must he wash? 
4. If Adam wants to earn $83, how many cars must he wash? 

(a)
Amount that Adam will earn for washing every 5 cars
= 4 x 5 + 5
= $25

(b)
Number of sets of $25
= 29 ÷ 25
= 1 r 4

Number of cars in 1 set
= 1 x 5
= 5

Number of extra cars that he has to wash
= 4 ÷ 4
= 1

Total number of cars that Adam must wash
= 5 + 1
= 6

(c)
Number of sets of $25
= 75 ÷ 25
= 3 (Note that there is no remainder.)

Total number of cars that Adam must wash
= 3 x 5
= 15

(d)
If Adam wants to earn $83, how many cars must he wash?

Number of sets of $83
= 83 ÷ 25
= 3 r 8

Number of cars in 5 sets
= 3 x 5
= 15

Number of extra cars that he has to wash
= 8 ÷ 4
= 2

Total number of cars
= 15 + 2
= 17

Answer(s): (a) $25; (b) 6; (c) 15; (d) 17