At first, Pierre, Oliver and Ethan had the same amount of money. After Ethan spent some of his money, Pierre spent ³₈ of his money and Oliver spent ³₅ of his money, Pierre had $243 more than Oliver. In the end, the total amount of money the three boys had left was $1275. How much money did Ethan spend?

	Pierre	Oliver	Ethan	Total
Before	8x5 =  40 u	5x8 = 40 u	40 u
Change	- 3x5 = - 15 u	- 3x8 = - 24 u	- ?
After	5x5 = 25 u	2x8 = 16 u		$1275

The amount that Pierre and Oliver each had at first is the same.  Make the amount that they each had the same.  LCM of 8 and 5 is 40.

Amount that Pierre had more than Oliver in the end
= 25 u - 16 u
= 9 u

9 u = 243

1 u = 243 ÷ 9 = 27

Amount that Pierre and Oliver had in the end
= 25 u + 16 u
= 41 u
= 41 x 27
= $1107

Amount that Ethan had in the end
= 1275 - 1107
= $168

Amount that Ethan had at first
= 40 u
= 40 x 27
= $1080

Amount that Ethan spent
= 1080 - 168
= $912

Answer(s): $912