PSLE Jade had a basket of purple beads and grey beads in the ratio 17 : 8. She removed an equal number of purple beads and grey beads from the basket. The ratio of the number of purple beads and grey beads left in the basket became 7 : 3. What percentage of the beads were left in the basket?
|
Purple beads |
Grey beads |
Difference |
Total |
Before |
17x4 = 68 u |
8x4 = 32 u |
9x4 = 36 u |
25x4 = 100 u |
Change |
- 5 u |
- 5 u |
|
|
After |
7x9 = 63 u |
3x9 = 27 u |
4x9 = 36 u |
10x9 = 90 u |
When Jade removed an equal number of purple beads and grey beads, the difference between the number of purple beads and grey beads at first and in the end remains the same.
LCM of 9 and 4 is 36.
Percentage of the beads left in the basket
=
90100 x 100%
= 910 x 100%
= 90%
Answer: 90%