If Risa gives Wesley $36, the amount of money she has will be 10% of his. If Wesley gives Risa $162, he will have the same amount of money as her. How much money did each of them have?
(a) Wesley
(b) Risa

	Case 1		Case 2
	Wesley	Risa	Wesley	Risa
Before	10 u - 36	1 u + 36	5.5 u + 162	5.5 u - 162
Change	+ 36	- 36	- 162	+ 162
After	10 u	1 u	5.5 u	5.5 u

(a)
10% = ¹⁰₁₀₀ = ¹₁₀

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

In Case 2, when Wesley gives to Risa, there is an internal transfer of money from Wesley to Risa. 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 Risa and Wesley have
= 10 u + 1 u
= 11 u

Amount that Risa and Wesley each has in the end for Case 2
= 11 u ÷ 2
= 5.5 u

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

10 u - 36 = 5.5 u + 162
10 u - 5.5 u = 162 + 36
4.5 u = 198 

1 u = 198 ÷ 4.5 = 44

Amount that Wesley has
= 10 u - 36
= 10 x 44 - 36
= 440 - 36
= $404 

(b)
Amount that Risa has
= 1 u + 36
= 1 x 44 + 36
= 44 + 36
= $80

Answer(s): (a) $404; (b) $80