Adam has 20 blue beads and 280 green beads.
After buying the same number of beads,
the ratio of the blue beads and the green beads becomes 3 : 7.
How many beads does he buy?
|
Blue |
Green |
Difference |
Before |
20 |
280 |
260 |
Change |
+ ? |
+ ? |
|
After |
3 u |
7 u |
4 u |
At first
Difference in the number of beads
= 280 - 20
= 260
In the end
Number of blue beads = 3 u
Number of green 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 blue beads and the green beads remains unchanged.
4 u = 260
1 u = 260 ÷ 4 = 65
Number of blue beads that Adam buys
= 3 u - 20
= 3 x 65 - 20
= 195 - 20
= 175
Total number of beads that Adam buys
= 2 x 175
= 350
Answer(s): 350