If Kylie gives Andy $28, the amount of money she has will be 30% of his. If Andy gives Kylie $140, he will have the same amount of money as her. How much money did each of them have?
(a) Andy
(b) Kylie

	Case 1		Case 2
	Andy	Kylie	Andy	Kylie
Before	10 u - 28	3 u + 28	6.5 u + 140	6.5 u - 140
Change	+ 28	- 28	- 140	+ 140
After	10 u	3 u	6.5 u	6.5 u

(a)
30% = ³⁰₁₀₀ = ³₁₀

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

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

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

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

10 u - 28 = 6.5 u + 140
10 u - 6.5 u = 140 + 28
3.5 u = 168 

1 u = 168 ÷ 3.5 = 48

Amount that Andy has
= 10 u - 28
= 10 x 48 - 28
= 480 - 28
= $452 

(b)
Amount that Kylie has
= 3 u + 28
= 3 x 48 + 28
= 144 + 28
= $172

Answer(s): (a) $452; (b) $172