At first, Charlie, Julian and Ben had the same amount of money. After Ben spent some of his money, Charlie spent ²₇ of his money and Julian spent ³₅ of his money, Charlie had $231 more than Julian. In the end, the total amount of money the three boys had left was $856. How much money did Ben spend?

	Charlie	Julian	Ben	Total
Before	7x5 =  35 u	5x7 = 35 u	35 u
Change	- 2x5 = - 10 u	- 3x7 = - 21 u	- ?
After	5x5 = 25 u	2x7 = 14 u		$856

The amount that Charlie and Julian 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 Charlie had more than Julian in the end
= 25 u - 14 u
= 11 u

11 u = 231

1 u = 231 ÷ 11 = 21

Amount that Charlie and Julian had in the end
= 25 u + 14 u
= 39 u
= 39 x 21
= $819

Amount that Ben had in the end
= 856 - 819
= $37

Amount that Ben had at first
= 35 u
= 35 x 21
= $735

Amount that Ben spent
= 735 - 37
= $698

Answer(s): $698