If Yoko gives Lee $17, the amount of money she has will be 10% of his. If Lee gives Yoko $163, he will have the same amount of money as her. How much money did each of them have?
(a) Lee
(b) Yoko

	Case 1		Case 2
	Lee	Yoko	Lee	Yoko
Before	10 u - 17	1 u + 17	5.5 u + 163	5.5 u - 163
Change	+ 17	- 17	- 163	+ 163
After	10 u	1 u	5.5 u	5.5 u

(a)
10% = ¹⁰₁₀₀ = ¹₁₀

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

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

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

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

10 u - 17 = 5.5 u + 163
10 u - 5.5 u = 163 + 17
4.5 u = 180 

1 u = 180 ÷ 4.5 = 40

Amount that Lee has
= 10 u - 17
= 10 x 40 - 17
= 400 - 17
= $383 

(b)
Amount that Yoko has
= 1 u + 17
= 1 x 40 + 17
= 40 + 17
= $57

Answer(s): (a) $383; (b) $57