Vaidev has 2 more 10-cent coins than 5-cent coins. After he used 20 of his 10-cent coins, the total value of 10-cent coins is $4.90 more than the total value of 5-cent coins. How many coins did he have in the end?

	10¢	5¢
Before	1 u + 2	1 u
Change	- 20
After	1 u - 18	1 u

	10¢	5¢
Number	1 u - 18	1 u
Value	10	5
Total value	10 u - 180	5 u

$1 = 100¢
$4.90 = 490¢

Number of 10¢ coins in the end
= 1 u + 2 - 20
= 1 u - 18

Total value of 10¢ coins in the end
= 10 x (1 u - 18)
= 10 u - 180

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

After using 20 10-cent coins, the value of 10-cent coins is 490¢ more than the value of 5-cent coins. If another 490¢ is added to the 5-cent coins, the total value of 10-cent coins and 5-cent coins will be the same.

10 u - 180 = 5 u + 490
10 u - 5 u = 490 + 180
5 u = 670

1 u = 670 ÷ 5 = 134

Number of coins that Vaidev had in the end
= 1 u + 1 u - 18
= 2 u - 18
= (2 x 134) - 18
= 268 - 18
= 250

Answer(s): 250