The ratio of the number of green stamps to blue stamps is 8 : 3. After Tom gives away 20 green stamps and buys another 60 blue stamps, there is equal number of green stamps and blue stamps. How many stamps does Tom have now?
| |
Green |
Blue |
| Before |
8 u |
3 u |
| Change |
- 20 |
+ 60 |
| After |
8 u - 20 |
3 u + 60 |
The number of green stamps and blue stamps in the end is the same.
8 u - 20 = 3 u + 60
8 u - 3 u = 60 + 20
5 u = 80
1 u = 80 ÷ 5 = 16
Number of stamps that Tom has now
= 8 u - 20 + 3 u + 60
= 8 u + 3 u - 20 + 60
= 11 u + 40
= 11 x 16 + 40
= 176 + 40
= 216
Answer(s): 216
