Cody has 4 more 20-cent coins than 10-cent coins. After he used 17 of his 20-cent coins, the total value of 20-cent coins is $4.30 more than the total value of 10-cent coins. How many coins did he have in the end?
|
20¢ |
10¢ |
Before |
1 u + 4 |
1 u |
Change |
- 17 |
|
After |
1 u - 13 |
1 u |
|
20¢ |
10¢ |
Number |
1 u - 13 |
1 u |
Value |
20 |
10 |
Total value |
20 u - 260 |
10 u |
$1 = 100¢
$4.30 = 430¢
Number of 20¢ coins in the end
= 1 u + 4 - 17
= 1 u - 13
Total value of 20¢ coins in the end
= 20 x (1 u - 13)
= 20 u - 260
Total value of 10¢ coins in the end
= 10 x 1 u
= 10 u
After using 17 20-cent coins, the value of 20-cent coins is 430¢ more than the value of 10-cent coins. If another 430¢ is added to the 10-cent coins, the total value of 20-cent coins and 10-cent coins will be the same.
20 u - 260 = 10 u + 430
20 u - 10 u = 430 + 260
10 u = 690
1 u = 690 ÷ 10 = 69
Number of coins that Cody had in the end
= 1 u + 1 u - 13
= 2 u - 13
= (2 x 69) - 13
= 138 - 13
= 125
Answer(s): 125