Expert: Abe Mantell - 12/30/2005

Question
please tell me the simplest way to solve the following problem.
(Mr sim pays $337.50 for a number of files. He can  buy 10 more files with the same amount of money if each file costs 20 cents less.How much
does he pay for a file and how many files does he buy?)

Answer
Hello Mostafa,

Let x=the number of files purchased, and
let y= the cost per file. Thus,

1. xy=337.50, and
2. (x+10)(y-0.20)=337.50

Let's take the 1st equation and solve for y:
y=337.50/x, now substitute into the 2nd equation.
(x+10)(337.50/x-0.20)=337.50, distributing
337.5-0.2x+3375/x-2=337.5...now solve for x.
x=-135, 125...thus x=125 files, and y=$2.70

OK??

Abe