The ratio of the number of green stickers to blue stickers is 5 : 2. After Mark gives away 40 green stickers and buys another 80 blue stickers, there is equal number of green stickers and blue stickers. How many stickers does Mark have now?
| |
Green |
Blue |
| Before |
5 u |
2 u |
| Change |
- 40 |
+ 80 |
| After |
5 u - 40 |
2 u + 80 |
The number of green stickers and blue stickers in the end is the same.
5 u - 40 = 2 u + 80
5 u - 2 u = 80 + 40
3 u = 120
1 u = 120 ÷ 3 = 40
Number of stickers that Mark has now
= 5 u - 40 + 2 u + 80
= 5 u + 2 u - 40 + 80
= 7 u + 40
= 7 x 40 + 40
= 280 + 40
= 320
Answer(s): 320
