PSLE Risa had a bag of blue beads and grey beads in the ratio 16 : 9. She removed an equal number of blue beads and grey beads from the bag. The ratio of the number of blue beads and grey beads left in the bag became 9 : 2. What percentage of the beads were left in the bag?
|
Blue beads |
Grey beads |
Difference |
Total |
Before |
16x1 = 16 u |
9x1 = 9 u |
7x1 = 7 u |
25x1 = 25 u |
Change |
- 7 u |
- 7 u |
|
|
After |
9x1 = 9 u |
2x1 = 2 u |
7x1 = 7 u |
11x1 = 11 u |
When Risa removed an equal number of blue beads and grey beads, the difference between the number of blue beads and grey beads at first and in the end remains the same.
LCM of 7 and 7 is 7.
Percentage of the beads left in the bag
=
1125 x 100%
= 1125 x 100%
= 44%
Answer: 44%