Eric has 10 more 50-cent coins than 20-cent coins. After he used 20 of his 50-cent coins, the total value of 50-cent coins is $3.40 more than the total value of 20-cent coins. How many coins did he have in the end?
|
50¢ |
20¢ |
Before |
1 u + 10 |
1 u |
Change |
- 20 |
|
After |
1 u - 10 |
1 u |
|
50¢ |
20¢ |
Number |
1 u - 10 |
1 u |
Value |
50 |
20 |
Total value |
50 u - 500 |
20 u |
$1 = 100¢
$3.40 = 340¢
Number of 50¢ coins in the end
= 1 u + 10 - 20
= 1 u - 10
Total value of 50¢ coins in the end
= 50 x (1 u - 10)
= 50 u - 500
Total value of 20¢ coins in the end
= 20 x 1 u
= 20 u
After using 20 50-cent coins, the value of 50-cent coins is 340¢ more than the value of 20-cent coins. If another 340¢ is added to the 20-cent coins, the total value of 50-cent coins and 20-cent coins will be the same.
50 u - 500 = 20 u + 340
50 u - 20 u = 340 + 500
30 u = 840
1 u = 840 ÷ 30 = 28
Number of coins that Eric had in the end
= 1 u + 1 u - 10
= 2 u - 10
= (2 x 28) - 10
= 56 - 10
= 46
Answer(s): 46