PSLE Jen had a bag of gold beads and purple beads in the ratio 18 : 7. She removed an equal number of gold beads and purple beads from the bag. The ratio of the number of gold beads and purple beads left in the bag became 5 : 1. What percentage of the beads were left in the bag?
|
Gold beads |
Purple beads |
Difference |
Total |
Before |
18x4 = 72 u |
7x4 = 28 u |
11x4 = 44 u |
25x4 = 100 u |
Change |
- 17 u |
- 17 u |
|
|
After |
5x11 = 55 u |
1x11 = 11 u |
4x11 = 44 u |
6x11 = 66 u |
When Jen removed an equal number of gold beads and purple beads, the difference between the number of gold beads and purple beads at first and in the end remains the same.
LCM of 11 and 4 is 44.
Percentage of the beads left in the bag
=
66100 x 100%
= 3350 x 100%
= 66%
Answer: 66%