At first, Tommy, Harry and Simon had the same amount of money. After Simon spent some of his money, Tommy spent ²₇ of his money and Harry spent ¹₂ of his money, Tommy had $39 more than Harry. In the end, the total amount of money the three boys had left was $294. How much money did Simon spend?

	Tommy	Harry	Simon	Total
Before	7x2 =  14 u	2x7 = 14 u	14 u
Change	- 2x2 = - 4 u	- 1x7 = - 7 u	- ?
After	5x2 = 10 u	1x7 = 7 u		$294

The amount that Tommy and Harry 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 Tommy had more than Harry in the end
= 10 u - 7 u
= 3 u

3 u = 39

1 u = 39 ÷ 3 = 13

Amount that Tommy and Harry had in the end
= 10 u + 7 u
= 17 u
= 17 x 13
= $221

Amount that Simon had in the end
= 294 - 221
= $73

Amount that Simon had at first
= 14 u
= 14 x 13
= $182

Amount that Simon spent
= 182 - 73
= $109

Answer(s): $109