Coin Box K contains 20-cent coins and Coin Box L contains 5-cent coins. There are 30 more coins in Coin Box L than in Coin Box K. The amount of money in Coin Box K is 240¢ more than the amount of money in Coin Box L. How many total coins are there?
| |
Coin Box K |
Coin Box L |
| Number |
1 u |
1 u + 30 |
| Value |
20¢ |
5¢ |
| Total value |
20 u |
5 u + 150 |
Total value of 20¢ coins in Coin Box K
= 20 x 1 u
= 20 u
Total value of 5¢ coins in Coin Box L
= 5 x (1 u + 30)
= 5 u + 150
The amount in Coin Box K is 240¢ more than Coin Box L. If another 240¢ is added into Coin Box L, both Coin Box K and Coin Box L will have the same amounts of money.
20 u = 5 u + 150 + 240
20 u - 5 u = 150 + 240
15 u = 390
1 u = 390 ÷ 15 = 26
Total number of coins
= 1 u + (1 u + 30)
= 2 u + 30
= 2 x 26 + 30
= 52 + 30
= 82
Answer(s): 82
