PSLE Wendy had a basket of black beads and purple beads in the ratio 13 : 7. She removed an equal number of black beads and purple beads from the basket. The ratio of the number of black beads and purple beads left in the basket became 4 : 1. What percentage of the beads were left in the basket?
|
Black beads |
Purple beads |
Difference |
Total |
Before |
13x1 = 13 u |
7x1 = 7 u |
6x1 = 6 u |
20x1 = 20 u |
Change |
- 5 u |
- 5 u |
|
|
After |
4x2 = 8 u |
1x2 = 2 u |
3x2 = 6 u |
5x2 = 10 u |
When Wendy removed an equal number of black beads and purple beads, the difference between the number of black beads and purple beads at first and in the end remains the same.
LCM of 6 and 3 is 6.
Percentage of the beads left in the basket
=
1020 x 100%
= 12 x 100%
= 50%
Answer: 50%