The ratio of the number of green pens to blue pens is 7 : 5. After Flynn gives away 30 green pens and buys another 80 blue pens, there is equal number of green pens and blue pens. How many pens does Flynn have now?
| |
Green |
Blue |
| Before |
7 u |
5 u |
| Change |
- 30 |
+ 80 |
| After |
7 u - 30 |
5 u + 80 |
The number of green pens and blue pens in the end is the same.
7 u - 30 = 5 u + 80
7 u - 5 u = 80 + 30
2 u = 110
1 u = 110 ÷ 2 = 55
Number of pens that Flynn has now
= 7 u - 30 + 5 u + 80
= 7 u + 5 u - 30 + 80
= 12 u + 50
= 12 x 55 + 50
= 660 + 50
= 710
Answer(s): 710
