The number of ten-cent coins in a coin box was ¹₄ the number of twenty-cent coins. Luis took out 22 twenty-cent coins and exchanged them for ten-cent coins. Then he put the money back into the coin box. The number of twenty-cent coins became ²₅ the number of ten-cent coins. How much money was there in the coin box?

	Make u the same (1)x4 = (3)	10-cent (1)	20-cent (2)
Before	4 u	1 u	4 u
Change	+ 176	+ 44	- 22
After	20 p	5 p	2 p

Value of 20-cent coins to be exchanged to 10-cent coins
= 22 x 20
= 440

Number of 10-cent coins to be exchanged from the 20-cent coins
= 440 ÷ 10
= 44

(3) = (2)
20 p - 176 = 2 p + 22
20 p - 2 p = 22 + 176
18 p = 198

1 p = 198 ÷ 18 = 11

Number of 10-cent coins in the end
= 5 p
= 5 p x 11
= 55

Value of 10-cent coins in the end
= 55 x 10
= 550¢

Number of 20-cent coins in the end
= 2 p
= 2 x 11
= 22

Value of 20-cent coins in the end
= 22 x 20
= 440¢

Total value of coins
= 550 + 440
= 990¢

$1 = 100¢
990¢ = $9.90 

Answer(s): $9.90