Fabian has 4 more 50-cent coins than 10-cent coins. After he used 6 of his 50-cent coins, the total value of 50-cent coins is $3.80 more than the total value of 10-cent coins. How many coins did he have in the end?

	50¢	10¢
Before	1 u + 4	1 u
Change	- 6
After	1 u - 2	1 u

	50¢	10¢
Number	1 u - 2	1 u
Value	50	10
Total value	50 u - 100	10 u

$1 = 100¢
$3.80 = 380¢

Number of 50¢ coins in the end
= 1 u + 4 - 6
= 1 u - 2

Total value of 50¢ coins in the end
= 50 x (1 u - 2)
= 50 u - 100

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

After using 6 50-cent coins, the value of 50-cent coins is 380¢ more than the value of 10-cent coins. If another 380¢ is added to the 10-cent coins, the total value of 50-cent coins and 10-cent coins will be the same.

50 u - 100 = 10 u + 380
50 u - 10 u = 380 + 100
40 u = 480

1 u = 480 ÷ 40 = 12

Number of coins that Fabian had in the end
= 1 u + 1 u - 2
= 2 u - 2
= (2 x 12) - 2
= 24 - 2
= 22

Answer(s): 22