At first, Wesley, Ken and Oscar had the same amount of money. After Oscar spent some of his money, Wesley spent ²₇ of his money and Ken spent ¹₂ of his money, Wesley had $90 more than Ken. In the end, the total amount of money the three boys had left was $653. How much money did Oscar spend?

	Wesley	Ken	Oscar	Total
Before	7x2 =  14 u	2x7 = 14 u	14 u
Change	- 2x2 = - 4 u	- 1x7 = - 7 u	- ?
After	5x2 = 10 u	1x7 = 7 u		$653

The amount that Wesley and Ken each had at first is the same.  Make the amount that they each had the same.  LCM of 7 and 2 is 14.

Amount that Wesley had more than Ken in the end
= 10 u - 7 u
= 3 u

3 u = 90

1 u = 90 ÷ 3 = 30

Amount that Wesley and Ken had in the end
= 10 u + 7 u
= 17 u
= 17 x 30
= $510

Amount that Oscar had in the end
= 653 - 510
= $143

Amount that Oscar had at first
= 14 u
= 14 x 30
= $420

Amount that Oscar spent
= 420 - 143
= $277

Answer(s): $277