Coin Box D contains only 50-cent coins and Coin Box E contains only 10-cent coins. There are 12 more coins in Coin Box E than in Coin Box D. The amount of money in Coin Box D is $2.80 more than the amount of money in Coin Box E. Find the total amount of money in both coin boxes.
| |
Coin Box D |
Coin Box E |
| Number |
1 u |
1 u + 12 |
| Value |
50¢ |
10¢ |
| Total value |
50 u |
10 u + 120 |
$1 = 100¢
$2.80 = 280¢
Total value of 50¢ coins in Coin Box D
= 50 x 1 u
= 50 u
Total value of 10¢ coins in Coin Box E
= 10(1 u + 12)
= 10 u + 120
The amount of money in Coin Box D is $2.80 more than the amount of money in Coin Box E. If another 280¢ is added into Coin Box E, the total value of coins in Coin Box D and Coin Box E will be the same.
50 u = 10 u + 120 + 280
50 u - 10 u = 400
40 u = 400
1 u = 400 ÷ 40 = 10
Total amount in both coin boxes
= 50 u + (10 u + 120)
= 60 u + 120
= (60 x 10) + 120
= 600 + 120
= 720¢
720¢ = $7.20
Answer(s): $7.20
