PSLE Wendy had a bag of silver balls and yellow balls in the ratio 17 : 8. She removed an equal number of silver balls and yellow balls from the bag. The ratio of the number of silver balls and yellow balls left in the bag became 4 : 1. What percentage of the balls were left in the bag?
|
Silver balls |
Yellow balls |
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 Wendy removed an equal number of silver balls and yellow balls, the difference between the number of silver balls and yellow balls at first and in the end remains the same.
LCM of 9 and 3 is 9.
Percentage of the balls left in the bag
=
1525 x 100%
= 35 x 100%
= 60%
Answer: 60%