Coin Box N contains 20-cent coins and Coin Box P contains 10-cent coins. There are 12 more coins in Coin Box P than in Coin Box N. The amount of money in Coin Box N is 40¢ more than the amount of money in Coin Box P. How many total coins are there?
| |
Coin Box N |
Coin Box P |
| Number |
1 u |
1 u + 12 |
| Value |
20¢ |
10¢ |
| Total value |
20 u |
10 u + 120 |
Total value of 20¢ coins in Coin Box N
= 20 x 1 u
= 20 u
Total value of 10¢ coins in Coin Box P
= 10 x (1 u + 12)
= 10 u + 120
The amount in Coin Box N is 40¢ more than Coin Box P. If another 40¢ is added into Coin Box P, both Coin Box N and Coin Box P will have the same amounts of money.
20 u = 10 u + 120 + 40
20 u - 10 u = 120 + 40
10 u = 160
1 u = 160 ÷ 10 = 16
Total number of coins
= 1 u + (1 u + 12)
= 2 u + 12
= 2 x 16 + 12
= 32 + 12
= 44
Answer(s): 44
