PSLE Usha had a box of brown beads and grey beads in the ratio 17 : 8. She removed an equal number of brown beads and grey beads from the box. The ratio of the number of brown beads and grey beads left in the box became 9 : 1. What percentage of the beads were left in the box?
|
Brown beads |
Grey beads |
Difference |
Total |
Before |
17x8 = 136 u |
8x8 = 64 u |
9x8 = 72 u |
25x8 = 200 u |
Change |
- 55 u |
- 55 u |
|
|
After |
9x9 = 81 u |
1x9 = 9 u |
8x9 = 72 u |
10x9 = 90 u |
When Usha removed an equal number of brown beads and grey beads, the difference between the number of brown beads and grey beads at first and in the end remains the same.
LCM of 9 and 8 is 72.
Percentage of the beads left in the box
=
90200 x 100%
= 920 x 100%
= 45%
Answer: 45%