PSLE Vanessa had a basket of gold balls and silver balls in the ratio 16 : 9. She removed an equal number of gold balls and silver balls from the basket. The ratio of the number of gold balls and silver balls left in the basket became 9 : 5. What percentage of the balls were left in the basket?
|
Gold 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 Vanessa removed an equal number of gold balls and silver balls, the difference between the number of gold 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%