PSLE Emma had a box of grey beads and purple beads in the ratio 16 : 9. She removed an equal number of grey beads and purple beads from the box. The ratio of the number of grey beads and purple beads left in the box became 3 : 1. What percentage of the beads were left in the box?
|
Grey beads |
Purple beads |
Difference |
Total |
Before |
16x2 = 32 u |
9x2 = 18 u |
7x2 = 14 u |
25x2 = 50 u |
Change |
- 11 u |
- 11 u |
|
|
After |
3x7 = 21 u |
1x7 = 7 u |
2x7 = 14 u |
4x7 = 28 u |
When Emma removed an equal number of grey beads and purple beads, the difference between the number of grey beads and purple beads at first and in the end remains the same.
LCM of 7 and 2 is 14.
Percentage of the beads left in the box
=
2850 x 100%
= 1425 x 100%
= 56%
Answer: 56%