PSLE Gwen had a box of grey beads and blue beads in the ratio 17 : 8. She removed an equal number of grey beads and blue beads from the box. The ratio of the number of grey beads and blue beads left in the box became 4 : 1. What percentage of the beads were left in the box?
|
Grey beads |
Blue beads |
Difference |
Total |
Before |
17x1 = 17 u |
8x1 = 8 u |
9x1 = 9 u |
25x1 = 25 u |
Change |
- 5 u |
- 5 u |
|
|
After |
4x3 = 12 u |
1x3 = 3 u |
3x3 = 9 u |
5x3 = 15 u |
When Gwen removed an equal number of grey beads and blue beads, the difference between the number of grey beads and blue beads at first and in the end remains the same.
LCM of 9 and 3 is 9.
Percentage of the beads left in the box
=
1525 x 100%
= 35 x 100%
= 60%
Answer: 60%