If Fanny gives Sean $36, the amount of money she has will be 25% of his. If Sean gives Fanny $36, he will have the same amount of money as her. How much money did each of them have?
(a) Sean
(b) Fanny

	Case 1		Case 2
	Sean	Fanny	Sean	Fanny
Before	4 u - 36	1 u + 36	2.5 u + 36	2.5 u - 36
Change	+ 36	- 36	- 36	+ 36
After	4 u	1 u	2.5 u	2.5 u

(a)
25% = ²⁵₁₀₀ = ¹₄

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

In Case 2, when Sean gives to Fanny, there is an internal transfer of money from Sean to Fanny. 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 Fanny and Sean have
= 4 u + 1 u
= 5 u

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

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

4 u - 36 = 2.5 u + 36
4 u - 2.5 u = 36 + 36
1.5 u = 72 

1 u = 72 ÷ 1.5 = 48

Amount that Sean has
= 4 u - 36
= 4 x 48 - 36
= 192 - 36
= $156 

(b)
Amount that Fanny has
= 1 u + 36
= 1 x 48 + 36
= 48 + 36
= $84

Answer(s): (a) $156; (b) $84