Bryan has 7 more 20-cent coins than 5-cent coins. After he used 19 of his 20-cent coins, the total value of 20-cent coins is $2.70 more than the total value of 5-cent coins. How many coins did he have in the end?
|
20¢ |
5¢ |
Before |
1 u + 7 |
1 u |
Change |
- 19 |
|
After |
1 u - 12 |
1 u |
|
20¢ |
5¢ |
Number |
1 u - 12 |
1 u |
Value |
20 |
5 |
Total value |
20 u - 240 |
5 u |
$1 = 100¢
$2.70 = 270¢
Number of 20¢ coins in the end
= 1 u + 7 - 19
= 1 u - 12
Total value of 20¢ coins in the end
= 20 x (1 u - 12)
= 20 u - 240
Total value of 5¢ coins in the end
= 5 x 1 u
= 5 u
After using 19 20-cent coins, the value of 20-cent coins is 270¢ more than the value of 5-cent coins. If another 270¢ is added to the 5-cent coins, the total value of 20-cent coins and 5-cent coins will be the same.
20 u - 240 = 5 u + 270
20 u - 5 u = 270 + 240
15 u = 510
1 u = 510 ÷ 15 = 34
Number of coins that Bryan had in the end
= 1 u + 1 u - 12
= 2 u - 12
= (2 x 34) - 12
= 68 - 12
= 56
Answer(s): 56