Question 1187280
Billy had some money. He spent $260 on a coat and 3/7 of the remainder on a
backpack. He had 1/5 of his money left. How much money did Billy have at
first?
------------------------
He had D dollars to start.
Then D - 260
Then 4/7 of D-260 after spending 3/7 = 4*(D-260)/7
And 4*(D-260)/7 = D/5
======================
4*(D60)/7 = D/5
20*(D-260)/7 = D
20*(D-260) = 7D
20D - 5200 = 7D
13D = 5200
D = $400
----------------------------
In this case, remainder and "money left" are the same.  It can be written:
Billy had some money. He spent $260 on a coat and 3/7 of the money left on a
backpack. 
He had 1/5 of his money left. How much money did Billy have at
first?