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