Adam has 40 red beads and 200 blue beads.
After buying the same number of beads,
the ratio of the red beads and the blue beads becomes 2 : 7.
How many beads does he buy?
|
Red |
Blue |
Difference |
Before |
40 |
200 |
160 |
Change |
+ ? |
+ ? |
|
After |
2 u |
7 u |
5 u |
At first
Difference in the number of beads
= 200 - 40
= 160
In the end
Number of red beads = 2 u
Number of blue beads = 7 u
Difference in the number of beads in units
= 7 u - 2 u
= 5 u
The difference in the number of beads between the red beads and the blue beads remains unchanged.
5 u = 160
1 u = 160 ÷ 5 = 32
Number of red beads that Adam buys
= 2 u - 40
= 2 x 32 - 40
= 64 - 40
= 24
Total number of beads that Adam buys
= 2 x 24
= 48
Answer(s): 48