Fabian has 7 more 10-cent coins than 5-cent coins. After he used 12 of his 10-cent coins, the total value of 10-cent coins is $1.80 more than the total value of 5-cent coins. How many coins did he have in the end?
|
10¢ |
5¢ |
Before |
1 u + 7 |
1 u |
Change |
- 12 |
|
After |
1 u - 5 |
1 u |
|
10¢ |
5¢ |
Number |
1 u - 5 |
1 u |
Value |
10 |
5 |
Total value |
10 u - 50 |
5 u |
$1 = 100¢
$1.80 = 180¢
Number of 10¢ coins in the end
= 1 u + 7 - 12
= 1 u - 5
Total value of 10¢ coins in the end
= 10 x (1 u - 5)
= 10 u - 50
Total value of 5¢ coins in the end
= 5 x 1 u
= 5 u
After using 12 10-cent coins, the value of 10-cent coins is 180¢ more than the value of 5-cent coins. If another 180¢ is added to the 5-cent coins, the total value of 10-cent coins and 5-cent coins will be the same.
10 u - 50 = 5 u + 180
10 u - 5 u = 180 + 50
5 u = 230
1 u = 230 ÷ 5 = 46
Number of coins that Fabian had in the end
= 1 u + 1 u - 5
= 2 u - 5
= (2 x 46) - 5
= 92 - 5
= 87
Answer(s): 87