Caden has 2 more 10-cent coins than 5-cent coins. After he used 10 of his 10-cent coins, the total value of 10-cent coins is $4.20 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 |
- 10 |
|
| After |
1 u - 8 |
1 u |
| |
10¢ |
5¢ |
| Number |
1 u - 8 |
1 u |
| Value |
10 |
5 |
| Total value |
10 u - 80 |
5 u |
$1 = 100¢
$4.20 = 420¢
Number of 10¢ coins in the end
= 1 u + 2 - 10
= 1 u - 8
Total value of 10¢ coins in the end
= 10 x (1 u - 8)
= 10 u - 80
Total value of 5¢ coins in the end
= 5 x 1 u
= 5 u
After using 10 10-cent coins, the value of 10-cent coins is 420¢ more than the value of 5-cent coins. If another 420¢ is added to the 5-cent coins, the total value of 10-cent coins and 5-cent coins will be the same.
10 u - 80 = 5 u + 420
10 u - 5 u = 420 + 80
5 u = 500
1 u = 500 ÷ 5 = 100
Number of coins that Caden had in the end
= 1 u + 1 u - 8
= 2 u - 8
= (2 x 100) - 8
= 200 - 8
= 192
Answer(s): 192
