The ratio of the number of blue stamps to red stamps is 9 : 5. After Wesley gives away 30 blue stamps and buys another 90 red stamps, there is equal number of blue stamps and red stamps. How many stamps does Wesley have now?
| |
Blue |
Red |
| Before |
9 u |
5 u |
| Change |
- 30 |
+ 90 |
| After |
9 u - 30 |
5 u + 90 |
The number of blue stamps and red stamps in the end is the same.
9 u - 30 = 5 u + 90
9 u - 5 u = 90 + 30
4 u = 120
1 u = 120 ÷ 4 = 30
Number of stamps that Wesley has now
= 9 u - 30 + 5 u + 90
= 9 u + 5 u - 30 + 90
= 14 u + 60
= 14 x 30 + 60
= 420 + 60
= 480
Answer(s): 480
