Bag C contains 20-cent coins and Bag D contains 10-cent coins. There are 18 more coins in Bag D than in Bag C. The amount of money in Bag C is 70¢ more than the amount of money in Bag D. How many total coins are there?
| |
Bag C |
Bag D |
| Number |
1 u |
1 u + 18 |
| Value |
20¢ |
10¢ |
| Total value |
20 u |
10 u + 180 |
Total value of 20¢ coins in Bag C
= 20 x 1 u
= 20 u
Total value of 10¢ coins in Bag D
= 10 x (1 u + 18)
= 10 u + 180
The amount in Bag C is 70¢ more than Bag D. If another 70¢ is added into Bag D, both Bag C and Bag D will have the same amounts of money.
20 u = 10 u + 180 + 70
20 u - 10 u = 180 + 70
10 u = 250
1 u = 250 ÷ 10 = 25
Total number of coins
= 1 u + (1 u + 18)
= 2 u + 18
= 2 x 25 + 18
= 50 + 18
= 68
Answer(s): 68
