PSLE Diana had a box of yellow balls and pink balls in the ratio 16 : 9. She removed an equal number of yellow balls and pink balls from the box. The ratio of the number of yellow balls and pink balls left in the box became 3 : 1. What percentage of the balls were left in the box?
|
Yellow balls |
Pink balls |
Difference |
Total |
Before |
16x2 = 32 u |
9x2 = 18 u |
7x2 = 14 u |
25x2 = 50 u |
Change |
- 11 u |
- 11 u |
|
|
After |
3x7 = 21 u |
1x7 = 7 u |
2x7 = 14 u |
4x7 = 28 u |
When Diana removed an equal number of yellow balls and pink balls, the difference between the number of yellow balls and pink balls at first and in the end remains the same.
LCM of 7 and 2 is 14.
Percentage of the balls left in the box
=
2850 x 100%
= 1425 x 100%
= 56%
Answer: 56%