The ratio of the number of red stickers to blue stickers is 7 : 3.
After Adam gives away 90 red stickers and 10 blue stickers,
there is an equal number of red stickers and blue stickers.
How many stickers does Adam have now?
|
Red |
Blue |
Before |
7 u |
3 u |
Change |
- 90 |
- 10 |
After |
7 u - 90 |
3 u - 10 |
The number of red stickers and blue stickers in the end is the same.
7 u - 90 = 3 u - 10
7 u - 3 u = 90 - 10
4 u = 80
1 u = 80 ÷ 4 = 20
Number of stickers that Adam has now
= 7 u - 90 + 3 u - 10
= 7 u + 3 u - 90 - 10
= 10 u - 100
= 10 x 20 - 100
= 200 - 100
= 100
Answer(s): 100