The ratio of the number of red stickers to green stickers is 7 : 5.
After Adam gives away 90 red stickers and 10 green stickers,
there is an equal number of red stickers and green stickers.
How many stickers does Adam have now?
|
Red |
Green |
Before |
7 u |
5 u |
Change |
- 90 |
- 10 |
After |
7 u - 90 |
5 u - 10 |
The number of red stickers and green stickers in the end is the same.
7 u - 90 = 5 u - 10
7 u - 5 u = 90 - 10
2 u = 80
1 u = 80 ÷ 2 = 40
Number of stickers that Adam has now
= 7 u - 90 + 5 u - 10
= 7 u + 5 u - 90 - 10
= 12 u - 100
= 12 x 40 - 100
= 480 - 100
= 380
Answer(s): 380