Daniel has 3 more 50-cent coins than 20-cent coins. After he used 18 of his 50-cent coins, the total value of 50-cent coins is $2.40 more than the total value of 20-cent coins. How many coins did he have in the end?
|
50¢ |
20¢ |
Before |
1 u + 3 |
1 u |
Change |
- 18 |
|
After |
1 u - 15 |
1 u |
|
50¢ |
20¢ |
Number |
1 u - 15 |
1 u |
Value |
50 |
20 |
Total value |
50 u - 750 |
20 u |
$1 = 100¢
$2.40 = 240¢
Number of 50¢ coins in the end
= 1 u + 3 - 18
= 1 u - 15
Total value of 50¢ coins in the end
= 50 x (1 u - 15)
= 50 u - 750
Total value of 20¢ coins in the end
= 20 x 1 u
= 20 u
After using 18 50-cent coins, the value of 50-cent coins is 240¢ more than the value of 20-cent coins. If another 240¢ is added to the 20-cent coins, the total value of 50-cent coins and 20-cent coins will be the same.
50 u - 750 = 20 u + 240
50 u - 20 u = 240 + 750
30 u = 990
1 u = 990 ÷ 30 = 33
Number of coins that Daniel had in the end
= 1 u + 1 u - 15
= 2 u - 15
= (2 x 33) - 15
= 66 - 15
= 51
Answer(s): 51