PSLE Shiyun had a bag of gold beads and silver beads in the ratio 13 : 9. She removed an equal number of gold beads and silver beads from the bag. The ratio of the number of gold beads and silver beads left in the bag became 8 : 3. What percentage of the beads were left in the bag?
|
Gold beads |
Silver beads |
Difference |
Total |
Before |
13x5 = 65 u |
9x5 = 45 u |
4x5 = 20 u |
22x5 = 110 u |
Change |
- 33 u |
- 33 u |
|
|
After |
8x4 = 32 u |
3x4 = 12 u |
5x4 = 20 u |
11x4 = 44 u |
When Shiyun removed an equal number of gold beads and silver beads, the difference between the number of gold beads and silver beads at first and in the end remains the same.
LCM of 4 and 5 is 20.
Percentage of the beads left in the bag
=
44110 x 100%
= 25 x 100%
= 40%
Answer: 40%