Justin has 9 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 $4.30 more than the total value of 5-cent coins. How many coins did he have at first?
|
50¢ |
5¢ |
Before |
1 u + 9 |
1 u |
Change |
- 13 |
|
After |
1 u - 4 |
1 u |
|
50¢ |
5¢ |
Number |
1 u - 4 |
1 u |
Value |
50 |
5 |
Total value |
50 u - 200 |
5 u |
$1 = 100¢
$4.30 = 430¢
Number of 50¢ coins in the end
= 1 u + 9 - 13
= 1 u - 4
Total value of 50¢ coins in the end
= 50 x (1 u - 4)
= 50 u - 200
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 430¢ more than the value of 5-cent coins. If another 430¢ is added to the 5-cent coins, the total value of 50-cent coins and 5-cent coins will be the same.
50 u - 200 = 5 u + 430
50 u - 5 u = 430 + 200
45 u = 630
1 u = 630 ÷ 45 = 14
Number of coins that Justin had at first
= 1 u + 1 u + 9
= 2 u + 9
= (2 x 14) + 9
= 28 + 9
= 37
Answer(s): 37