Coin Box R contains only 50-cent coins and Coin Box S contains only 5-cent coins. There are 21 more coins in Coin Box S than in Coin Box R. The amount of money in Coin Box R is $3.45 more than the amount of money in Coin Box S. Find the total amount of money in both coin boxes.
| |
Coin Box R |
Coin Box S |
| Number |
1 u |
1 u + 21 |
| Value |
50¢ |
5¢ |
| Total value |
50 u |
5 u + 105 |
$1 = 100¢
$3.45 = 345¢
Total value of 50¢ coins in Coin Box R
= 50 x 1 u
= 50 u
Total value of 5¢ coins in Coin Box S
= 5(1 u + 21)
= 5 u + 105
The amount of money in Coin Box R is $3.45 more than the amount of money in Coin Box S. If another 345¢ is added into Coin Box S, the total value of coins in Coin Box R and Coin Box S will be the same.
50 u = 5 u + 105 + 345
50 u - 5 u = 450
45 u = 450
1 u = 450 ÷ 45 = 10
Total amount in both coin boxes
= 50 u + (5 u + 105)
= 55 u + 105
= (55 x 10) + 105
= 550 + 105
= 655¢
655¢ = $6.55
Answer(s): $6.55
