Adam has 40 red stickers and 140 green stickers.
After buying the same number of stickers,
the ratio of the red stickers and the green stickers becomes 3 : 8.
How many stickers does he buy?
|
Red |
Green |
Difference |
Before |
40 |
140 |
100 |
Change |
+ ? |
+ ? |
|
After |
3 u |
8 u |
5 u |
At first
Difference in the number of stickers
= 140 - 40
= 100
In the end
Number of red stickers = 3 u
Number of green stickers = 8 u
Difference in the number of stickers in units
= 8 u - 3 u
= 5 u
The difference in the number of stickers between the red stickers and the green stickers remains unchanged.
5 u = 100
1 u = 100 ÷ 5 = 20
Number of red stickers that Adam buys
= 3 u - 40
= 3 x 20 - 40
= 60 - 40
= 20
Total number of stickers that Adam buys
= 2 x 20
= 40
Answer(s): 40