PSLE Sabrina had a bag of yellow balls and grey balls in the ratio 16 : 9. She removed an equal number of yellow balls and grey balls from the bag. The ratio of the number of yellow balls and grey balls left in the bag became 10 : 3. What percentage of the balls were left in the bag?
|
Yellow balls |
Grey balls |
Difference |
Total |
Before |
16x1 = 16 u |
9x1 = 9 u |
7x1 = 7 u |
25x1 = 25 u |
Change |
- 6 u |
- 6 u |
|
|
After |
10x1 = 10 u |
3x1 = 3 u |
7x1 = 7 u |
13x1 = 13 u |
When Sabrina removed an equal number of yellow balls and grey balls, the difference between the number of yellow balls and grey balls at first and in the end remains the same.
LCM of 7 and 7 is 7.
Percentage of the balls left in the bag
=
1325 x 100%
= 1325 x 100%
= 52%
Answer: 52%