PSLE Sarah had a basket of purple marbles and silver marbles in the ratio 17 : 8. She removed an equal number of purple marbles and silver marbles from the basket. The ratio of the number of purple marbles and silver marbles left in the basket became 5 : 2. What percentage of the marbles were left in the basket?
|
Purple marbles |
Silver marbles |
Difference |
Total |
Before |
17x1 = 17 u |
8x1 = 8 u |
9x1 = 9 u |
25x1 = 25 u |
Change |
- 2 u |
- 2 u |
|
|
After |
5x3 = 15 u |
2x3 = 6 u |
3x3 = 9 u |
7x3 = 21 u |
When Sarah removed an equal number of purple marbles and silver marbles, the difference between the number of purple marbles and silver marbles at first and in the end remains the same.
LCM of 9 and 3 is 9.
Percentage of the marbles left in the basket
=
2125 x 100%
= 2125 x 100%
= 84%
Answer: 84%