Ken has 2 more 10-cent coins than 5-cent coins. After he used 4 of his 10-cent coins, the total value of 10-cent coins is $4.60 more than the total value of 5-cent coins. How many coins did he have at first?
| |
10¢ |
5¢ |
| Before |
1 u + 2 |
1 u |
| Change |
- 4 |
|
| After |
1 u - 2 |
1 u |
| |
10¢ |
5¢ |
| Number |
1 u - 2 |
1 u |
| Value |
10 |
5 |
| Total value |
10 u - 20 |
5 u |
$1 = 100¢
$4.60 = 460¢
Number of 10¢ coins in the end
= 1 u + 2 - 4
= 1 u - 2
Total value of 10¢ coins in the end
= 10 x (1 u - 2)
= 10 u - 20
Total value of 5¢ coins in the end
= 5 x 1 u
= 5 u
After using 4 10-cent coins, the value of 10-cent coins is 460¢ more than the value of 5-cent coins. If another 460¢ is added to the 5-cent coins, the total value of 10-cent coins and 5-cent coins will be the same.
10 u - 20 = 5 u + 460
10 u - 5 u = 460 + 20
5 u = 480
1 u = 480 ÷ 5 = 96
Number of coins that Ken had at first
= 1 u + 1 u + 2
= 2 u + 2
= (2 x 96) + 2
= 192 + 2
= 194
Answer(s): 194
