Neave has 5 more 50-cent coins than 5-cent coins. After he used 13 of his 50-cent coins, the total value of 50-cent coins is $3.20 more than the total value of 5-cent coins. How many coins did he have in the end?
|
50¢ |
5¢ |
Before |
1 u + 5 |
1 u |
Change |
- 13 |
|
After |
1 u - 8 |
1 u |
|
50¢ |
5¢ |
Number |
1 u - 8 |
1 u |
Value |
50 |
5 |
Total value |
50 u - 400 |
5 u |
$1 = 100¢
$3.20 = 320¢
Number of 50¢ coins in the end
= 1 u + 5 - 13
= 1 u - 8
Total value of 50¢ coins in the end
= 50 x (1 u - 8)
= 50 u - 400
Total value of 5¢ coins in the end
= 5 x 1 u
= 5 u
After using 13 50-cent coins, the value of 50-cent coins is 320¢ more than the value of 5-cent coins. If another 320¢ is added to the 5-cent coins, the total value of 50-cent coins and 5-cent coins will be the same.
50 u - 400 = 5 u + 320
50 u - 5 u = 320 + 400
45 u = 720
1 u = 720 ÷ 45 = 16
Number of coins that Neave had in the end
= 1 u + 1 u - 8
= 2 u - 8
= (2 x 16) - 8
= 32 - 8
= 24
Answer(s): 24