Ahmad has 2 more 20-cent coins than 5-cent coins. After he used 13 of his 20-cent coins, the total value of 20-cent coins is $1.40 more than the total value of 5-cent coins. How many coins did he have at first?
|
20¢ |
5¢ |
Before |
1 u + 2 |
1 u |
Change |
- 13 |
|
After |
1 u - 11 |
1 u |
|
20¢ |
5¢ |
Number |
1 u - 11 |
1 u |
Value |
20 |
5 |
Total value |
20 u - 220 |
5 u |
$1 = 100¢
$1.40 = 140¢
Number of 20¢ coins in the end
= 1 u + 2 - 13
= 1 u - 11
Total value of 20¢ coins in the end
= 20 x (1 u - 11)
= 20 u - 220
Total value of 5¢ coins in the end
= 5 x 1 u
= 5 u
After using 13 20-cent coins, the value of 20-cent coins is 140¢ more than the value of 5-cent coins. If another 140¢ is added to the 5-cent coins, the total value of 20-cent coins and 5-cent coins will be the same.
20 u - 220 = 5 u + 140
20 u - 5 u = 140 + 220
15 u = 360
1 u = 360 ÷ 15 = 24
Number of coins that Ahmad had at first
= 1 u + 1 u + 2
= 2 u + 2
= (2 x 24) + 2
= 48 + 2
= 50
Answer(s): 50