Gabriel has 3 more 10-cent coins than 5-cent coins. After he used 17 of his 10-cent coins, the total value of 10-cent coins is $1.40 more than the total value of 5-cent coins. How many coins did he have at first?

	10¢	5¢
Before	1 u + 3	1 u
Change	- 17
After	1 u - 14	1 u

	10¢	5¢
Number	1 u - 14	1 u
Value	10	5
Total value	10 u - 140	5 u

$1 = 100¢
$1.40 = 140¢

Number of 10¢ coins in the end
= 1 u + 3 - 17
= 1 u - 14

Total value of 10¢ coins in the end
= 10 x (1 u - 14)
= 10 u - 140

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

After using 17 10-cent coins, the value of 10-cent coins is 140¢ more than the value of 5-cent coins. If another 140¢ is added to the 5-cent coins, the total value of 10-cent coins and 5-cent coins will be the same.

10 u - 140 = 5 u + 140
10 u - 5 u = 140 + 140
5 u = 280

1 u = 280 ÷ 5 = 56

Number of coins that Gabriel had at first
= 1 u + 1 u + 3
= 2 u + 3
= (2 x 56) + 3
= 112 + 3
= 115

Answer(s): 115