PSLE Kylie had a bag of red beads and brown beads in the ratio 17 : 9. She removed an equal number of red beads and brown beads from the bag. The ratio of the number of red beads and brown beads left in the bag became 9 : 4. What percentage of the beads were left in the bag?
|
Red beads |
Brown beads |
Difference |
Total |
Before |
17x5 = 85 u |
9x5 = 45 u |
8x5 = 40 u |
26x5 = 130 u |
Change |
- 13 u |
- 13 u |
|
|
After |
9x8 = 72 u |
4x8 = 32 u |
5x8 = 40 u |
13x8 = 104 u |
When Kylie removed an equal number of red beads and brown beads, the difference between the number of red beads and brown beads at first and in the end remains the same.
LCM of 8 and 5 is 40.
Percentage of the beads left in the bag
=
104130 x 100%
= 45 x 100%
= 80%
Answer: 80%