PSLE Eva had a basket of gold marbles and brown marbles in the ratio 17 : 7. She removed an equal number of gold marbles and brown marbles from the basket. The ratio of the number of gold marbles and brown marbles left in the basket became 7 : 2. What percentage of the marbles were left in the basket?
|
Gold marbles |
Brown marbles |
Difference |
Total |
Before |
17x1 = 17 u |
7x1 = 7 u |
10x1 = 10 u |
24x1 = 24 u |
Change |
- 3 u |
- 3 u |
|
|
After |
7x2 = 14 u |
2x2 = 4 u |
5x2 = 10 u |
9x2 = 18 u |
When Eva removed an equal number of gold marbles and brown marbles, the difference between the number of gold marbles and brown marbles at first and in the end remains the same.
LCM of 10 and 5 is 10.
Percentage of the marbles left in the basket
=
1824 x 100%
= 34 x 100%
= 75%
Answer: 75%