The ratio of the number of blue stickers to green stickers is 7 : 3. After Carl gives away 10 blue stickers and buys another 90 green stickers, there is equal number of blue stickers and green stickers. How many stickers does Carl have now?
| |
Blue |
Green |
| Before |
7 u |
3 u |
| Change |
- 10 |
+ 90 |
| After |
7 u - 10 |
3 u + 90 |
The number of blue stickers and green stickers in the end is the same.
7 u - 10 = 3 u + 90
7 u - 3 u = 90 + 10
4 u = 100
1 u = 100 ÷ 4 = 25
Number of stickers that Carl has now
= 7 u - 10 + 3 u + 90
= 7 u + 3 u - 10 + 90
= 10 u + 80
= 10 x 25 + 80
= 250 + 80
= 330
Answer(s): 330
