Simon has 3 more 50-cent coins than 20-cent coins. After he used 17 of his 50-cent coins, the total value of 50-cent coins is $2.60 more than the total value of 20-cent coins. How many coins did he have in the end?

	50¢	20¢
Before	1 u + 3	1 u
Change	- 17
After	1 u - 14	1 u

	50¢	20¢
Number	1 u - 14	1 u
Value	50	20
Total value	50 u - 700	20 u

$1 = 100¢
$2.60 = 260¢

Number of 50¢ coins in the end
= 1 u + 3 - 17
= 1 u - 14

Total value of 50¢ coins in the end
= 50 x (1 u - 14)
= 50 u - 700

Total value of 20¢ coins in the end
= 20 x 1 u
= 20 u

After using 17 50-cent coins, the value of 50-cent coins is 260¢ more than the value of 20-cent coins. If another 260¢ is added to the 20-cent coins, the total value of 50-cent coins and 20-cent coins will be the same.

50 u - 700 = 20 u + 260
50 u - 20 u = 260 + 700
30 u = 960

1 u = 960 ÷ 30 = 32

Number of coins that Simon had in the end
= 1 u + 1 u - 14
= 2 u - 14
= (2 x 32) - 14
= 64 - 14
= 50

Answer(s): 50