Bag J contains 50-cent coins and Bag K contains 10-cent coins. There are 20 more coins in Bag K than in Bag J. The amount of money in Bag J is 1000¢ more than the amount of money in Bag K. How many total coins are there?
| |
Bag J |
Bag K |
| Number |
1 u |
1 u + 20 |
| Value |
50¢ |
10¢ |
| Total value |
50 u |
10 u + 200 |
Total value of 50¢ coins in Bag J
= 50 x 1 u
= 50 u
Total value of 10¢ coins in Bag K
= 10 x (1 u + 20)
= 10 u + 200
The amount in Bag J is 1000¢ more than Bag K. If another 1000¢ is added into Bag K, both Bag J and Bag K will have the same amounts of money.
50 u = 10 u + 200 + 1000
50 u - 10 u = 200 + 1000
40 u = 1200
1 u = 1200 ÷ 40 = 30
Total number of coins
= 1 u + (1 u + 20)
= 2 u + 20
= 2 x 30 + 20
= 60 + 20
= 80
Answer(s): 80
