Answer:
22.5 + 7.5 = x
x= 30
Denise used 30 gallons to wash clothes
Explanation:
She mentions that 22.5 gallons is 7.5 LESS than what she used to wash clothes, if we add 7.5 gallons to 22.5 we get 30 gallons, therefor she used 30 gallons to wash clothes