The ratio of the number of green erasers to blue erasers is 8 : 5. After George gives away 10 green erasers and buys another 80 blue erasers, there is equal number of green erasers and blue erasers. How many erasers does George have now?
| |
Green |
Blue |
| Before |
8 u |
5 u |
| Change |
- 10 |
+ 80 |
| After |
8 u - 10 |
5 u + 80 |
The number of green erasers and blue erasers in the end is the same.
8 u - 10 = 5 u + 80
8 u - 5 u = 80 + 10
3 u = 90
1 u = 90 ÷ 3 = 30
Number of erasers that George has now
= 8 u - 10 + 5 u + 80
= 8 u + 5 u - 10 + 80
= 13 u + 70
= 13 x 30 + 70
= 390 + 70
= 460
Answer(s): 460
