In august the simons water bill was $48.in september it was 15% lower . what was the simons water bill in september

Water bill of Simons in the month of August = $48
Percentage of bill that was lower in the month of September = 15%
then
Amount of bill that was lower in the month of September = (15/100) * 48
                                                                                           = 720/100 dollars
                                                                                           = 7.2 dollars
So
The bill for the month of September = (48 - 7.2) dollars
                                                          = 40.8 dollars
So Simon will have to pay $40.8 as the water bill for the month of September. I hope the procedure is clear enough for you to understand.