Owen has 4 more 10-cent coins than 5-cent coins. After he used 6 of his 10-cent coins, the total value of 10-cent coins is $4.10 more than the total value of 5-cent coins. How many coins did he have in the end?
|
10¢ |
5¢ |
Before |
1 u + 4 |
1 u |
Change |
- 6 |
|
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¢
$4.10 = 410¢
Number of 10¢ coins in the end
= 1 u + 4 - 6
= 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 6 10-cent coins, the value of 10-cent coins is 410¢ more than the value of 5-cent coins. If another 410¢ 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 + 410
10 u - 5 u = 410 + 20
5 u = 430
1 u = 430 ÷ 5 = 86
Number of coins that Owen had in the end
= 1 u + 1 u - 2
= 2 u - 2
= (2 x 86) - 2
= 172 - 2
= 170
Answer(s): 170