If Jaslyn gives Ryan $21, the amount of money she has will be 25% of his. If Ryan gives Jaslyn $27, he will have the same amount of money as her. How much money did each of them have?
(a) Ryan
(b) Jaslyn

	Case 1		Case 2
	Ryan	Jaslyn	Ryan	Jaslyn
Before	4 u - 21	1 u + 21	2.5 u + 27	2.5 u - 27
Change	+ 21	- 21	- 27	+ 27
After	4 u	1 u	2.5 u	2.5 u

(a)
25% = ²⁵₁₀₀ = ¹₄

In Case 1, when Jaslyn gives to Ryan, there is an internal transfer of money from Jaslyn to Ryan.  The total amount that both have remains the same.

In Case 2, when Ryan gives to Jaslyn, there is an internal transfer of money from Ryan to Jaslyn. The total amount that both have remains the same.

The total amount that both have in Case 1 and Case 2 are the same.

Total amount that Jaslyn and Ryan have
= 4 u + 1 u
= 5 u

Amount that Jaslyn and Ryan each has in the end for Case 2
= 5 u ÷ 2
= 2.5 u

Amount that Ryan has at first is the same in Case 1 and Case 2.

4 u - 21 = 2.5 u + 27
4 u - 2.5 u = 27 + 21
1.5 u = 48 

1 u = 48 ÷ 1.5 = 32

Amount that Ryan has
= 4 u - 21
= 4 x 32 - 21
= 128 - 21
= $107 

(b)
Amount that Jaslyn has
= 1 u + 21
= 1 x 32 + 21
= 32 + 21
= $53

Answer(s): (a) $107; (b) $53