Bottle R contains 10-cent coins and Bottle S contains 5-cent coins. There are 17 more coins in Bottle S than in Bottle R. The amount of money in Bottle R is 15¢ more than the amount of money in Bottle S. How many total coins are there?
| |
Bottle R |
Bottle S |
| Number |
1 u |
1 u + 17 |
| Value |
10¢ |
5¢ |
| Total value |
10 u |
5 u + 85 |
Total value of 10¢ coins in Bottle R
= 10 x 1 u
= 10 u
Total value of 5¢ coins in Bottle S
= 5 x (1 u + 17)
= 5 u + 85
The amount in Bottle R is 15¢ more than Bottle S. If another 15¢ is added into Bottle S, both Bottle R and Bottle S will have the same amounts of money.
10 u = 5 u + 85 + 15
10 u - 5 u = 85 + 15
5 u = 100
1 u = 100 ÷ 5 = 20
Total number of coins
= 1 u + (1 u + 17)
= 2 u + 17
= 2 x 20 + 17
= 40 + 17
= 57
Answer(s): 57
