PSLE Shiyun had a bag of green beads and brown beads in the ratio 13 : 7. She removed an equal number of green beads and brown beads from the bag. The ratio of the number of green beads and brown beads left in the bag became 5 : 2. What percentage of the beads were left in the bag?
|
Green beads |
Brown beads |
Difference |
Total |
Before |
13x1 = 13 u |
7x1 = 7 u |
6x1 = 6 u |
20x1 = 20 u |
Change |
- 3 u |
- 3 u |
|
|
After |
5x2 = 10 u |
2x2 = 4 u |
3x2 = 6 u |
7x2 = 14 u |
When Shiyun removed an equal number of green beads and brown beads, the difference between the number of green beads and brown beads at first and in the end remains the same.
LCM of 6 and 3 is 6.
Percentage of the beads left in the bag
=
1420 x 100%
= 710 x 100%
= 70%
Answer: 70%