Bottle N contains 10-cent coins and Bottle P contains 5-cent coins. There are 13 more coins in Bottle P than in Bottle N. The amount of money in Bottle N is 85¢ more than the amount of money in Bottle P. How many total coins are there?
| |
Bottle N |
Bottle P |
| Number |
1 u |
1 u + 13 |
| Value |
10¢ |
5¢ |
| Total value |
10 u |
5 u + 65 |
Total value of 10¢ coins in Bottle N
= 10 x 1 u
= 10 u
Total value of 5¢ coins in Bottle P
= 5 x (1 u + 13)
= 5 u + 65
The amount in Bottle N is 85¢ more than Bottle P. If another 85¢ is added into Bottle P, both Bottle N and Bottle P will have the same amounts of money.
10 u = 5 u + 65 + 85
10 u - 5 u = 65 + 85
5 u = 150
1 u = 150 ÷ 5 = 30
Total number of coins
= 1 u + (1 u + 13)
= 2 u + 13
= 2 x 30 + 13
= 60 + 13
= 73
Answer(s): 73
