PSLE Jane had a basket of green marbles and white marbles in the ratio 13 : 7. She removed an equal number of green marbles and white marbles from the basket. The ratio of the number of green marbles and white marbles left in the basket became 9 : 4. What percentage of the marbles were left in the basket?
|
Green marbles |
White marbles |
Difference |
Total |
Before |
13x5 = 65 u |
7x5 = 35 u |
6x5 = 30 u |
20x5 = 100 u |
Change |
- 11 u |
- 11 u |
|
|
After |
9x6 = 54 u |
4x6 = 24 u |
5x6 = 30 u |
13x6 = 78 u |
When Jane removed an equal number of green marbles and white marbles, the difference between the number of green marbles and white marbles at first and in the end remains the same.
LCM of 6 and 5 is 30.
Percentage of the marbles left in the basket
=
78100 x 100%
= 3950 x 100%
= 78%
Answer: 78%