Nick has 2 more 50-cent coins than 20-cent coins. After he used 4 of his 50-cent coins, the total value of 50-cent coins is $2.90 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 |
- 4 |
|
After |
1 u - 2 |
1 u |
|
50¢ |
20¢ |
Number |
1 u - 2 |
1 u |
Value |
50 |
20 |
Total value |
50 u - 100 |
20 u |
$1 = 100¢
$2.90 = 290¢
Number of 50¢ coins in the end
= 1 u + 2 - 4
= 1 u - 2
Total value of 50¢ coins in the end
= 50 x (1 u - 2)
= 50 u - 100
Total value of 20¢ coins in the end
= 20 x 1 u
= 20 u
After using 4 50-cent coins, the value of 50-cent coins is 290¢ more than the value of 20-cent coins. If another 290¢ is added to the 20-cent coins, the total value of 50-cent coins and 20-cent coins will be the same.
50 u - 100 = 20 u + 290
50 u - 20 u = 290 + 100
30 u = 390
1 u = 390 ÷ 30 = 13
Number of coins that Nick had at first
= 1 u + 1 u + 2
= 2 u + 2
= (2 x 13) + 2
= 26 + 2
= 28
Answer(s): 28