Respuesta :

you earn $20 for washing 4 cars
You have to do a cross product to get your answer :

35$ → 7 cars
× $ → 4 cars

× $ = ( 35 × 4 ) ÷ 7

× $ = (140) ÷ 7

× $ = 20

So the answer is : You earn 20$ for washing 4 cars! ☻