PSLE Dana had a basket of grey marbles and yellow marbles in the ratio 16 : 9. She removed an equal number of grey marbles and yellow marbles from the basket. The ratio of the number of grey marbles and yellow marbles left in the basket became 9 : 5. What percentage of the marbles were left in the basket?
|
Grey marbles |
Yellow marbles |
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 Dana removed an equal number of grey marbles and yellow marbles, the difference between the number of grey marbles and yellow marbles at first and in the end remains the same.
LCM of 7 and 4 is 28.
Percentage of the marbles left in the basket
=
98100 x 100%
= 4950 x 100%
= 98%
Answer: 98%