They earned $30 from trucks because 5 x 6 = <<5*6=30>>30
They earned $35 from SUVs because 5 x 7 = <<5*7=35>>35
They earned $35 from cars because 100 - 35 - 30 = <<100-35-30=35>>35
They washed 7 cars because 35 / 5 = <<35/5=7>>7
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