PSLE Sabrina had a basket of gold balls and white balls in the ratio 17 : 9. She removed an equal number of gold balls and white balls from the basket. The ratio of the number of gold balls and white balls left in the basket became 9 : 4. What percentage of the balls were left in the basket?
|
Gold balls |
White 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 Sabrina removed an equal number of gold balls and white balls, the difference between the number of gold balls and white 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%