Neave has 2 more 50-cent coins than 10-cent coins. After he used 13 of his 50-cent coins, the total value of 50-cent coins is $4.50 more than the total value of 10-cent coins. How many coins did he have in the end?
| |
50¢ |
10¢ |
| Before |
1 u + 2 |
1 u |
| Change |
- 13 |
|
| After |
1 u - 11 |
1 u |
| |
50¢ |
10¢ |
| Number |
1 u - 11 |
1 u |
| Value |
50 |
10 |
| Total value |
50 u - 550 |
10 u |
$1 = 100¢
$4.50 = 450¢
Number of 50¢ coins in the end
= 1 u + 2 - 13
= 1 u - 11
Total value of 50¢ coins in the end
= 50 x (1 u - 11)
= 50 u - 550
Total value of 10¢ coins in the end
= 10 x 1 u
= 10 u
After using 13 50-cent coins, the value of 50-cent coins is 450¢ more than the value of 10-cent coins. If another 450¢ is added to the 10-cent coins, the total value of 50-cent coins and 10-cent coins will be the same.
50 u - 550 = 10 u + 450
50 u - 10 u = 450 + 550
40 u = 1000
1 u = 1000 ÷ 40 = 25
Number of coins that Neave had in the end
= 1 u + 1 u - 11
= 2 u - 11
= (2 x 25) - 11
= 50 - 11
= 39
Answer(s): 39
