If Tina gives Cody $33, the amount of money she has will be 40% of his. If Cody gives Tina $9, he will have the same amount of money as her. How much money did each of them have?
(a) Cody
(b) Tina

	Case 1		Case 2
	Cody	Tina	Cody	Tina
Before	5 u - 33	2 u + 33	3.5 u + 9	3.5 u - 9
Change	+ 33	- 33	- 9	+ 9
After	5 u	2 u	3.5 u	3.5 u

(a)
40% = ⁴⁰₁₀₀ = ²₅

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

In Case 2, when Cody gives to Tina, there is an internal transfer of money from Cody to Tina. 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 Tina and Cody have
= 5 u + 2 u
= 7 u

Amount that Tina and Cody each has in the end for Case 2
= 7 u ÷ 2
= 3.5 u

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

5 u - 33 = 3.5 u + 9
5 u - 3.5 u = 9 + 33
1.5 u = 42 

1 u = 42 ÷ 1.5 = 28

Amount that Cody has
= 5 u - 33
= 5 x 28 - 33
= 140 - 33
= $107 

(b)
Amount that Tina has
= 2 u + 33
= 2 x 28 + 33
= 56 + 33
= $89

Answer(s): (a) $107; (b) $89