Members of a senior class held a car wash to
raise funds for their senior prom. They charged
$3 to wash a car and $5 to wash a pick-up truck
or a sport utility vehicle. If they earned a total
of $275 by washing a total of 75 vehicles, how
many cars did they wash?

How would I solve this?

Question

Members of a senior class held a car wash to 
raise funds for their senior prom. They charged 
$3 to wash a car and $5 to wash a pick-up truck 
or a sport utility vehicle. If they earned a total 
of $275 by washing a total of 75 vehicles, how 
many cars did they wash? 

How would I solve this?

anonymous · Answer

put x = number of cars, then since the total is 75 there must have been $75-x$ trucks. 
solve 
$$3x+5(75-x)=275$$ for x