At first, Fred, Tommy and Ryan had the same amount of money. After Ryan spent some of his money, Fred spent ²₇ of his money and Tommy spent ²₃ of his money, Fred had $192 more than Tommy. In the end, the total amount of money the three boys had left was $576. How much money did Ryan spend?

	Fred	Tommy	Ryan	Total
Before	7x3 =  21 u	3x7 = 21 u	21 u
Change	- 2x3 = - 6 u	- 2x7 = - 14 u	- ?
After	5x3 = 15 u	1x7 = 7 u		$576

The amount that Fred and Tommy each had at first is the same.  Make the amount that they each had the same.  LCM of 7 and 3 is 21.

Amount that Fred had more than Tommy in the end
= 15 u - 7 u
= 8 u

8 u = 192

1 u = 192 ÷ 8 = 24

Amount that Fred and Tommy had in the end
= 15 u + 7 u
= 22 u
= 22 x 24
= $528

Amount that Ryan had in the end
= 576 - 528
= $48

Amount that Ryan had at first
= 21 u
= 21 x 24
= $504

Amount that Ryan spent
= 504 - 48
= $456

Answer(s): $456