PSLE Abi had a box of brown beads and yellow beads in the ratio 16 : 9. She removed an equal number of brown beads and yellow beads from the box. The ratio of the number of brown beads and yellow beads left in the box became 3 : 1. What percentage of the beads were left in the box?
|
Brown beads |
Yellow 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 Abi removed an equal number of brown beads and yellow beads, the difference between the number of brown beads and yellow 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%