Question 767682
June bill = x
July bill = x + 40
August bill = x - 10
Total:
x + (x + 40) + (x - 10) = 120
x + x + 40 + x - 10 = 120
3x + 30 = 120
3x = 120 - 30
3x = 90
x = 30
August bill was $20.
Hope this helps.
:-)