If Yoko gives Peter $35, the amount of money she has will be 30% of his. If Peter gives Yoko $63, he will have the same amount of money as her. How much money did each of them have?
(a) Peter
(b) Yoko

	Case 1		Case 2
	Peter	Yoko	Peter	Yoko
Before	10 u - 35	3 u + 35	6.5 u + 63	6.5 u - 63
Change	+ 35	- 35	- 63	+ 63
After	10 u	3 u	6.5 u	6.5 u

(a)
30% = ³⁰₁₀₀ = ³₁₀

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

In Case 2, when Peter gives to Yoko, there is an internal transfer of money from Peter 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 Peter have
= 10 u + 3 u
= 13 u

Amount that Yoko and Peter each has in the end for Case 2
= 13 u ÷ 2
= 6.5 u

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

10 u - 35 = 6.5 u + 63
10 u - 6.5 u = 63 + 35
3.5 u = 98 

1 u = 98 ÷ 3.5 = 28

Amount that Peter has
= 10 u - 35
= 10 x 28 - 35
= 280 - 35
= $245 

(b)
Amount that Yoko has
= 3 u + 35
= 3 x 28 + 35
= 84 + 35
= $119

Answer(s): (a) $245; (b) $119