Seth, Peter and Charlie had a total of 189 coins. The ratio of the number of coins that Peter had to the number of coins that Charlie had was 8 : 7. After Seth and Peter each gave away half of their coins, the 3 children had 133 coins left. How many coins did Peter and Charlie have at first?
| |
Seth |
Peter |
Charlie |
Total |
| Before |
2 p |
8 u |
7 u |
189 |
| Change |
- 1 p |
- 4 u |
|
- 56 |
| After |
1 p |
4 u |
7 u |
133 |
Total number of coins that Seth and Peter gave away
= 189 - 133
= 56
1 p + 4 u = 56 --- (1)
1 p + 4 u + 7 u = 133
1 p + 11 u = 133 --- (2)
(2) - (1)
(1 p + 11 u) - (1 p + 4 u) = 133 - 56
11 u - 4 u = 77
7 u = 77
1 u = 77 ÷ 7 = 11
Total number of coins that Peter and Charlie had at first
= 8 u + 7 u
= 15 u
= 15 x 11
= 165
Answer(s): 165
