Answer: 53 cars were washed.
Step-by-step explanation:
Given : The unit rate comparing dollars earned to cars washed is 6.
i.e. The fundraiser can earn $6 per car wash.
If the fundraiser earned $318, then the number of car wash he did is given by :-
[tex]\dfrac{318}{6}=53[/tex]
Hence, 53 cars were washed.