Adam has 30 red stickers and 120 green stickers.
After buying the same number of stickers,
the ratio of the red stickers and the green stickers becomes 3 : 5.
How many stickers does he buy?
|
Red |
Green |
Difference |
Before |
30 |
120 |
90 |
Change |
+ ? |
+ ? |
|
After |
3 u |
5 u |
2 u |
At first
Difference in the number of stickers
= 120 - 30
= 90
In the end
Number of red stickers = 3 u
Number of green stickers = 5 u
Difference in the number of stickers in units
= 5 u - 3 u
= 2 u
The difference in the number of stickers between the red stickers and the green stickers remains unchanged.
2 u = 90
1 u = 90 ÷ 2 = 45
Number of red stickers that Adam buys
= 3 u - 30
= 3 x 45 - 30
= 135 - 30
= 105
Total number of stickers that Adam buys
= 2 x 105
= 210
Answer(s): 210