The ratio of the number of blue stickers to green stickers is 3 : 1. After Andy gives away 40 blue stickers and buys another 70 green stickers, there is equal number of blue stickers and green stickers. How many stickers does Andy have now?
| |
Blue |
Green |
| Before |
3 u |
1 u |
| Change |
- 40 |
+ 70 |
| After |
3 u - 40 |
1 u + 70 |
The number of blue stickers and green stickers in the end is the same.
3 u - 40 = 1 u + 70
3 u - 1 u = 70 + 40
2 u = 110
1 u = 110 ÷ 2 = 55
Number of stickers that Andy has now
= 3 u - 40 + 1 u + 70
= 3 u + 1 u - 40 + 70
= 4 u + 30
= 4 x 55 + 30
= 220 + 30
= 250
Answer(s): 250
