Cole has 2 more 50-cent coins than 20-cent coins. After he used 9 of his 50-cent coins, the total value of 50-cent coins is $2.50 more than the total value of 20-cent coins. How many coins did he have at first?
| |
50¢ |
20¢ |
| Before |
1 u + 2 |
1 u |
| Change |
- 9 |
|
| After |
1 u - 7 |
1 u |
| |
50¢ |
20¢ |
| Number |
1 u - 7 |
1 u |
| Value |
50 |
20 |
| Total value |
50 u - 350 |
20 u |
$1 = 100¢
$2.50 = 250¢
Number of 50¢ coins in the end
= 1 u + 2 - 9
= 1 u - 7
Total value of 50¢ coins in the end
= 50 x (1 u - 7)
= 50 u - 350
Total value of 20¢ coins in the end
= 20 x 1 u
= 20 u
After using 9 50-cent coins, the value of 50-cent coins is 250¢ more than the value of 20-cent coins. If another 250¢ is added to the 20-cent coins, the total value of 50-cent coins and 20-cent coins will be the same.
50 u - 350 = 20 u + 250
50 u - 20 u = 250 + 350
30 u = 600
1 u = 600 ÷ 30 = 20
Number of coins that Cole had at first
= 1 u + 1 u + 2
= 2 u + 2
= (2 x 20) + 2
= 40 + 2
= 42
Answer(s): 42
