At first, Riordan, Ethan and Simon had the same amount of money. After Simon spent some of his money, Riordan spent ³₈ of his money and Ethan spent ³₄ of his money, Riordan had $84 more than Ethan. In the end, the total amount of money the three boys had left was $288. How much money did Simon spend?

	Riordan	Ethan	Simon	Total
Before	8x1 =  8 u	4x2 = 8 u	8 u
Change	- 3x1 = - 3 u	- 3x2 = - 6 u	- ?
After	5x1 = 5 u	1x2 = 2 u		$288

The amount that Riordan and Ethan each had at first is the same.  Make the amount that they each had the same.  LCM of 8 and 4 is 8.

Amount that Riordan had more than Ethan in the end
= 5 u - 2 u
= 3 u

3 u = 84

1 u = 84 ÷ 3 = 28

Amount that Riordan and Ethan had in the end
= 5 u + 2 u
= 7 u
= 7 x 28
= $196

Amount that Simon had in the end
= 288 - 196
= $92

Amount that Simon had at first
= 8 u
= 8 x 28
= $224

Amount that Simon spent
= 224 - 92
= $132

Answer(s): $132