PSLE Pamela had a bag of yellow beads and green beads in the ratio 13 : 7. She removed an equal number of yellow beads and green beads from the bag. The ratio of the number of yellow beads and green beads left in the bag became 7 : 3. What percentage of the beads were left in the bag?
|
Yellow beads |
Green beads |
Difference |
Total |
Before |
13x2 = 26 u |
7x2 = 14 u |
6x2 = 12 u |
20x2 = 40 u |
Change |
- 5 u |
- 5 u |
|
|
After |
7x3 = 21 u |
3x3 = 9 u |
4x3 = 12 u |
10x3 = 30 u |
When Pamela removed an equal number of yellow beads and green beads, the difference between the number of yellow beads and green beads at first and in the end remains the same.
LCM of 6 and 4 is 12.
Percentage of the beads left in the bag
=
3040 x 100%
= 34 x 100%
= 75%
Answer: 75%