The ratio of the number of green erasers to blue erasers is 9 : 5. After Nick gives away 60 green erasers and buys another 80 blue erasers, there is equal number of green erasers and blue erasers. How many erasers does Nick have now?
| |
Green |
Blue |
| Before |
9 u |
5 u |
| Change |
- 60 |
+ 80 |
| After |
9 u - 60 |
5 u + 80 |
The number of green erasers and blue erasers in the end is the same.
9 u - 60 = 5 u + 80
9 u - 5 u = 80 + 60
4 u = 140
1 u = 140 ÷ 4 = 35
Number of erasers that Nick has now
= 9 u - 60 + 5 u + 80
= 9 u + 5 u - 60 + 80
= 14 u + 20
= 14 x 35 + 20
= 490 + 20
= 510
Answer(s): 510
