Fabian has 2 more 20-cent coins than 10-cent coins. After he used 17 of his 20-cent coins, the total value of 20-cent coins is $4.40 more than the total value of 10-cent coins. How many coins did he have in the end?
|
20¢ |
10¢ |
Before |
1 u + 2 |
1 u |
Change |
- 17 |
|
After |
1 u - 15 |
1 u |
|
20¢ |
10¢ |
Number |
1 u - 15 |
1 u |
Value |
20 |
10 |
Total value |
20 u - 300 |
10 u |
$1 = 100¢
$4.40 = 440¢
Number of 20¢ coins in the end
= 1 u + 2 - 17
= 1 u - 15
Total value of 20¢ coins in the end
= 20 x (1 u - 15)
= 20 u - 300
Total value of 10¢ coins in the end
= 10 x 1 u
= 10 u
After using 17 20-cent coins, the value of 20-cent coins is 440¢ more than the value of 10-cent coins. If another 440¢ is added to the 10-cent coins, the total value of 20-cent coins and 10-cent coins will be the same.
20 u - 300 = 10 u + 440
20 u - 10 u = 440 + 300
10 u = 740
1 u = 740 ÷ 10 = 74
Number of coins that Fabian had in the end
= 1 u + 1 u - 15
= 2 u - 15
= (2 x 74) - 15
= 148 - 15
= 133
Answer(s): 133