Rael has 4 more 50-cent coins than 10-cent coins. After he used 20 of his 50-cent coins, the total value of 50-cent coins is $3.20 more than the total value of 10-cent coins. How many coins did he have in the end?
|
50¢ |
10¢ |
Before |
1 u + 4 |
1 u |
Change |
- 20 |
|
After |
1 u - 16 |
1 u |
|
50¢ |
10¢ |
Number |
1 u - 16 |
1 u |
Value |
50 |
10 |
Total value |
50 u - 800 |
10 u |
$1 = 100¢
$3.20 = 320¢
Number of 50¢ coins in the end
= 1 u + 4 - 20
= 1 u - 16
Total value of 50¢ coins in the end
= 50 x (1 u - 16)
= 50 u - 800
Total value of 10¢ coins in the end
= 10 x 1 u
= 10 u
After using 20 50-cent coins, the value of 50-cent coins is 320¢ more than the value of 10-cent coins. If another 320¢ is added to the 10-cent coins, the total value of 50-cent coins and 10-cent coins will be the same.
50 u - 800 = 10 u + 320
50 u - 10 u = 320 + 800
40 u = 1120
1 u = 1120 ÷ 40 = 28
Number of coins that Rael had in the end
= 1 u + 1 u - 16
= 2 u - 16
= (2 x 28) - 16
= 56 - 16
= 40
Answer(s): 40