The number of ten-cent coins in a tin can was ¹₄ the number of fifty-cent coins. Flynn took out 18 fifty-cent coins and exchanged them for ten-cent coins. Then he put the money back into the tin can. The number of fifty-cent coins became ²₅ the number of ten-cent coins. How much money was there in the tin can?

	Make u the same (1)x4 = (3)	10-cent (1)	50-cent (2)
Before	4 u	1 u	4 u
Change	+ 360	+ 90	- 18
After	20 p	5 p	2 p

Value of 50-cent coins to be exchanged to 10-cent coins
= 18 x 50
= 900

Number of 10-cent coins to be exchanged from the 50-cent coins
= 900 ÷ 10
= 90

(3) = (2)
20 p - 360 = 2 p + 18
20 p - 2 p = 18 + 360
18 p = 378

1 p = 378 ÷ 18 = 21

Number of 10-cent coins in the end
= 5 p
= 5 p x 21
= 105

Value of 10-cent coins in the end
= 105 x 10
= 1050¢

Number of 50-cent coins in the end
= 2 p
= 2 x 21
= 42

Value of 50-cent coins in the end
= 42 x 50
= 2100¢

Total value of coins
= 1050 + 2100
= 3150¢

$1 = 100¢
3150¢ = $31.50 

Answer(s): $31.50