PSLE Barbara had a box of blue beads and white beads in the ratio 16 : 9. She removed an equal number of blue beads and white beads from the box. The ratio of the number of blue beads and white beads left in the box became 8 : 1. What percentage of the beads were left in the box?
|
Blue beads |
White beads |
Difference |
Total |
Before |
16x1 = 16 u |
9x1 = 9 u |
7x1 = 7 u |
25x1 = 25 u |
Change |
- 8 u |
- 8 u |
|
|
After |
8x1 = 8 u |
1x1 = 1 u |
7x1 = 7 u |
9x1 = 9 u |
When Barbara removed an equal number of blue beads and white beads, the difference between the number of blue beads and white beads at first and in the end remains the same.
LCM of 7 and 7 is 7.
Percentage of the beads left in the box
=
925 x 100%
= 925 x 100%
= 36%
Answer: 36%