The number of twenty-cent coins in a pouch was ¹₃ the number of fifty-cent coins. Lee took out 24 fifty-cent coins and exchanged them for twenty-cent coins. Then he put the money back into the pouch. The number of fifty-cent coins became ³₅ the number of twenty-cent coins. How much money was there in the pouch?

	Make u the same (1)x3 = (3)	20-cent (1)	50-cent (2)
Before	3 u	1 u	3 u
Change	+ 180	+ 60	- 24
After	15 p	5 p	3 p

Value of 50-cent coins to be exchanged to 20-cent coins
= 24 x 50
= 1200

Number of 20-cent coins to be exchanged from the 50-cent coins
= 1200 ÷ 20
= 60

(3) = (2)
15 p - 180 = 3 p + 24
15 p - 3 p = 24 + 180
12 p = 204

1 p = 204 ÷ 12 = 17

Number of 20-cent coins in the end
= 5 p
= 5 p x 17
= 85

Value of 20-cent coins in the end
= 85 x 20
= 1700¢

Number of 50-cent coins in the end
= 3 p
= 3 x 17
= 51

Value of 50-cent coins in the end
= 51 x 50
= 2550¢

Total value of coins
= 1700 + 2550
= 4250¢

$1 = 100¢
4250¢ = $42.50 

Answer(s): $42.50