PSLE Gwen had a basket of pink balls and yellow balls in the ratio 17 : 9. She removed an equal number of pink balls and yellow balls from the basket. The ratio of the number of pink balls and yellow balls left in the basket became 9 : 4. What percentage of the balls were left in the basket?
|
Pink balls |
Yellow balls |
Difference |
Total |
Before |
17x5 = 85 u |
9x5 = 45 u |
8x5 = 40 u |
26x5 = 130 u |
Change |
- 13 u |
- 13 u |
|
|
After |
9x8 = 72 u |
4x8 = 32 u |
5x8 = 40 u |
13x8 = 104 u |
When Gwen removed an equal number of pink balls and yellow balls, the difference between the number of pink balls and yellow balls at first and in the end remains the same.
LCM of 8 and 5 is 40.
Percentage of the balls left in the basket
=
104130 x 100%
= 45 x 100%
= 80%
Answer: 80%