Adam has 30 red beads and 300 blue beads.
After buying the same number of beads,
the ratio of the red beads and the blue beads becomes 2 : 5.
How many beads does he buy?
|
Red |
Blue |
Difference |
Before |
30 |
300 |
270 |
Change |
+ ? |
+ ? |
|
After |
2 u |
5 u |
3 u |
At first
Difference in the number of beads
= 300 - 30
= 270
In the end
Number of red beads = 2 u
Number of blue 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 red beads and the blue beads remains unchanged.
3 u = 270
1 u = 270 ÷ 3 = 90
Number of red beads that Adam buys
= 2 u - 30
= 2 x 90 - 30
= 180 - 30
= 150
Total number of beads that Adam buys
= 2 x 150
= 300
Answer(s): 300