Paul has 4 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 $4.30 more than the total value of 5-cent coins. How many coins did he have at first?
|
10¢ |
5¢ |
Before |
1 u + 4 |
1 u |
Change |
- 10 |
|
After |
1 u - 6 |
1 u |
|
10¢ |
5¢ |
Number |
1 u - 6 |
1 u |
Value |
10 |
5 |
Total value |
10 u - 60 |
5 u |
$1 = 100¢
$4.30 = 430¢
Number of 10¢ coins in the end
= 1 u + 4 - 10
= 1 u - 6
Total value of 10¢ coins in the end
= 10 x (1 u - 6)
= 10 u - 60
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 430¢ more than the value of 5-cent coins. If another 430¢ is added to the 5-cent coins, the total value of 10-cent coins and 5-cent coins will be the same.
10 u - 60 = 5 u + 430
10 u - 5 u = 430 + 60
5 u = 490
1 u = 490 ÷ 5 = 98
Number of coins that Paul had at first
= 1 u + 1 u + 4
= 2 u + 4
= (2 x 98) + 4
= 196 + 4
= 200
Answer(s): 200