At first, Daniel, Xavier and Simon had the same amount of money. After Simon spent some of his money, Daniel spent ²₇ of his money and Xavier spent ²₅ of his money, Daniel had $108 more than Xavier. In the end, the total amount of money the three boys had left was $1380. How much money did Simon spend?

	Daniel	Xavier	Simon	Total
Before	7x5 =  35 u	5x7 = 35 u	35 u
Change	- 2x5 = - 10 u	- 2x7 = - 14 u	- ?
After	5x5 = 25 u	3x7 = 21 u		$1380

The amount that Daniel and Xavier each had at first is the same.  Make the amount that they each had the same.  LCM of 7 and 5 is 35.

Amount that Daniel had more than Xavier in the end
= 25 u - 21 u
= 4 u

4 u = 108

1 u = 108 ÷ 4 = 27

Amount that Daniel and Xavier had in the end
= 25 u + 21 u
= 46 u
= 46 x 27
= $1242

Amount that Simon had in the end
= 1380 - 1242
= $138

Amount that Simon had at first
= 35 u
= 35 x 27
= $945

Amount that Simon spent
= 945 - 138
= $807

Answer(s): $807