Adam earns $2 for every car he washes.
He gets $3 bonus for every 5 cars he washes.
- How much will Adam earn if he washes every 5 cars?
- If Adam wants to earn $21, how many cars must he wash?
- If Adam wants to earn $39, how many cars must he wash?
- If Adam wants to earn $28, how many cars must he wash?
(a)
Amount that Adam will earn for washing every 5 cars
= 2 x 5 + 3
= $13
(b)
Number of sets of $13
= 21 ÷ 13
= 1 r 8
Number of cars in 1 set
= 1 x 5
= 5
Number of extra cars that he has to wash
= 8 ÷ 2
= 4
Total number of cars that Adam must wash
= 5 + 4
= 9
(c)
Number of sets of $13
= 39 ÷ 13
= 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 $28, how many cars must he wash?
Number of sets of $28
= 28 ÷ 13
= 2 r 2
Number of cars in 5 sets
= 2 x 5
= 10
Number of extra cars that he has to wash
= 2 ÷ 2
= 1
Total number of cars
= 10 + 1
= 11
Answer(s): (a) $13; (b) 9; (c) 15; (d) 11