PSLE Raeann had a basket of pink balls and silver balls in the ratio 16 : 9. She removed an equal number of pink balls and silver balls from the basket. The ratio of the number of pink balls and silver balls left in the basket became 9 : 5. What percentage of the balls were left in the basket?
|
Pink balls |
Silver balls |
Difference |
Total |
Before |
16x4 = 64 u |
9x4 = 36 u |
7x4 = 28 u |
25x4 = 100 u |
Change |
- 1 u |
- 1 u |
|
|
After |
9x7 = 63 u |
5x7 = 35 u |
4x7 = 28 u |
14x7 = 98 u |
When Raeann removed an equal number of pink balls and silver balls, the difference between the number of pink balls and silver balls at first and in the end remains the same.
LCM of 7 and 4 is 28.
Percentage of the balls left in the basket
=
98100 x 100%
= 4950 x 100%
= 98%
Answer: 98%