Luke has 8 more 50-cent coins than 5-cent coins. After he used 18 of his 50-cent coins, the total value of 50-cent coins is $1.30 more than the total value of 5-cent coins. How many coins did he have in the end?

	50¢	5¢
Before	1 u + 8	1 u
Change	- 18
After	1 u - 10	1 u

	50¢	5¢
Number	1 u - 10	1 u
Value	50	5
Total value	50 u - 500	5 u

$1 = 100¢
$1.30 = 130¢

Number of 50¢ coins in the end
= 1 u + 8 - 18
= 1 u - 10

Total value of 50¢ coins in the end
= 50 x (1 u - 10)
= 50 u - 500

Total value of 5¢ coins in the end
= 5 x 1 u
= 5 u

After using 18 50-cent coins, the value of 50-cent coins is 130¢ more than the value of 5-cent coins. If another 130¢ is added to the 5-cent coins, the total value of 50-cent coins and 5-cent coins will be the same.

50 u - 500 = 5 u + 130
50 u - 5 u = 130 + 500
45 u = 630

1 u = 630 ÷ 45 = 14

Number of coins that Luke had in the end
= 1 u + 1 u - 10
= 2 u - 10
= (2 x 14) - 10
= 28 - 10
= 18

Answer(s): 18