If Wendy gives Brandon $21, the amount of money she has will be 30% of his. If Brandon gives Wendy $112, he will have the same amount of money as her. How much money did each of them have?
(a) Brandon
(b) Wendy

	Case 1		Case 2
	Brandon	Wendy	Brandon	Wendy
Before	10 u - 21	3 u + 21	6.5 u + 112	6.5 u - 112
Change	+ 21	- 21	- 112	+ 112
After	10 u	3 u	6.5 u	6.5 u

(a)
30% = ³⁰₁₀₀ = ³₁₀

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

In Case 2, when Brandon gives to Wendy, there is an internal transfer of money from Brandon to Wendy. 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 Wendy and Brandon have
= 10 u + 3 u
= 13 u

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

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

10 u - 21 = 6.5 u + 112
10 u - 6.5 u = 112 + 21
3.5 u = 133 

1 u = 133 ÷ 3.5 = 38

Amount that Brandon has
= 10 u - 21
= 10 x 38 - 21
= 380 - 21
= $359 

(b)
Amount that Wendy has
= 3 u + 21
= 3 x 38 + 21
= 114 + 21
= $135

Answer(s): (a) $359; (b) $135