PSLE Jade had a bag of silver marbles and green marbles in the ratio 13 : 7. She removed an equal number of silver marbles and green marbles from the bag. The ratio of the number of silver marbles and green marbles left in the bag became 3 : 1. What percentage of the marbles were left in the bag?
|
Silver marbles |
Green marbles |
Difference |
Total |
Before |
13x1 = 13 u |
7x1 = 7 u |
6x1 = 6 u |
20x1 = 20 u |
Change |
- 4 u |
- 4 u |
|
|
After |
3x3 = 9 u |
1x3 = 3 u |
2x3 = 6 u |
4x3 = 12 u |
When Jade removed an equal number of silver marbles and green marbles, the difference between the number of silver marbles and green marbles at first and in the end remains the same.
LCM of 6 and 2 is 6.
Percentage of the marbles left in the bag
=
1220 x 100%
= 35 x 100%
= 60%
Answer: 60%