Coin Box Q contains 50-cent coins and Coin Box R contains 10-cent coins. There are 15 more coins in Coin Box R than in Coin Box Q. The amount of money in Coin Box Q is 810¢ more than the amount of money in Coin Box R. How many total coins are there?
| |
Coin Box Q |
Coin Box R |
| Number |
1 u |
1 u + 15 |
| Value |
50¢ |
10¢ |
| Total value |
50 u |
10 u + 150 |
Total value of 50¢ coins in Coin Box Q
= 50 x 1 u
= 50 u
Total value of 10¢ coins in Coin Box R
= 10 x (1 u + 15)
= 10 u + 150
The amount in Coin Box Q is 810¢ more than Coin Box R. If another 810¢ is added into Coin Box R, both Coin Box Q and Coin Box R will have the same amounts of money.
50 u = 10 u + 150 + 810
50 u - 10 u = 150 + 810
40 u = 960
1 u = 960 ÷ 40 = 24
Total number of coins
= 1 u + (1 u + 15)
= 2 u + 15
= 2 x 24 + 15
= 48 + 15
= 63
Answer(s): 63
