The ratio of the number of green stamps to blue stamps is 3 : 1. After Ahmad gives away 50 green stamps and buys another 80 blue stamps, there is equal number of green stamps and blue stamps. How many stamps does Ahmad have now?
| |
Green |
Blue |
| Before |
3 u |
1 u |
| Change |
- 50 |
+ 80 |
| After |
3 u - 50 |
1 u + 80 |
The number of green stamps and blue stamps in the end is the same.
3 u - 50 = 1 u + 80
3 u - 1 u = 80 + 50
2 u = 130
1 u = 130 ÷ 2 = 65
Number of stamps that Ahmad has now
= 3 u - 50 + 1 u + 80
= 3 u + 1 u - 50 + 80
= 4 u + 30
= 4 x 65 + 30
= 260 + 30
= 290
Answer(s): 290
