Adam has 40 green beads and 130 red beads.
After buying the same number of beads,
the ratio of the green beads and the red beads becomes 2 : 5.
How many beads does he buy?
|
Green |
Red |
Difference |
Before |
40 |
130 |
90 |
Change |
+ ? |
+ ? |
|
After |
2 u |
5 u |
3 u |
At first
Difference in the number of beads
= 130 - 40
= 90
In the end
Number of green beads = 2 u
Number of red beads = 5 u
Difference in the number of beads in units
= 5 u - 2 u
= 3 u
The difference in the number of beads between the green beads and the red beads remains unchanged.
3 u = 90
1 u = 90 ÷ 3 = 30
Number of green beads that Adam buys
= 2 u - 40
= 2 x 30 - 40
= 60 - 40
= 20
Total number of beads that Adam buys
= 2 x 20
= 40
Answer(s): 40