Adam has 80 green beads and 200 blue beads.
After buying the same number of beads,
the ratio of the green beads and the blue beads becomes 3 : 7.
How many beads does he buy?
|
Green |
Blue |
Difference |
Before |
80 |
200 |
120 |
Change |
+ ? |
+ ? |
|
After |
3 u |
7 u |
4 u |
At first
Difference in the number of beads
= 200 - 80
= 120
In the end
Number of green beads = 3 u
Number of blue beads = 7 u
Difference in the number of beads in units
= 7 u - 3 u
= 4 u
The difference in the number of beads between the green beads and the blue beads remains unchanged.
4 u = 120
1 u = 120 ÷ 4 = 30
Number of green beads that Adam buys
= 3 u - 80
= 3 x 30 - 80
= 90 - 80
= 10
Total number of beads that Adam buys
= 2 x 10
= 20
Answer(s): 20