Adam has 20 green beads and 280 red beads.
After buying the same number of beads,
the ratio of the green beads and the red beads becomes 2 : 7.
How many beads does he buy?
|
Green |
Red |
Difference |
Before |
20 |
280 |
260 |
Change |
+ ? |
+ ? |
|
After |
2 u |
7 u |
5 u |
At first
Difference in the number of beads
= 280 - 20
= 260
In the end
Number of green beads = 2 u
Number of red 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 green beads and the red beads remains unchanged.
5 u = 260
1 u = 260 ÷ 5 = 52
Number of green beads that Adam buys
= 2 u - 20
= 2 x 52 - 20
= 104 - 20
= 84
Total number of beads that Adam buys
= 2 x 84
= 168
Answer(s): 168