Eric has 6 more 50-cent coins than 10-cent coins. After he used 17 of his 50-cent coins, the total value of 50-cent coins is $4.10 more than the total value of 10-cent coins. How many coins did he have at first?

	50¢	10¢
Before	1 u + 6	1 u
Change	- 17
After	1 u - 11	1 u

	50¢	10¢
Number	1 u - 11	1 u
Value	50	10
Total value	50 u - 550	10 u

$1 = 100¢
$4.10 = 410¢

Number of 50¢ coins in the end
= 1 u + 6 - 17
= 1 u - 11

Total value of 50¢ coins in the end
= 50 x (1 u - 11)
= 50 u - 550

Total value of 10¢ coins in the end
= 10 x 1 u
= 10 u

After using 17 50-cent coins, the value of 50-cent coins is 410¢ more than the value of 10-cent coins. If another 410¢ is added to the 10-cent coins, the total value of 50-cent coins and 10-cent coins will be the same.

50 u - 550 = 10 u + 410
50 u - 10 u = 410 + 550
40 u = 960

1 u = 960 ÷ 40 = 24

Number of coins that Eric had at first
= 1 u + 1 u + 6
= 2 u + 6
= (2 x 24) + 6
= 48 + 6
= 54

Answer(s): 54