PSLE Yoko had a bag of brown marbles and silver marbles in the ratio 16 : 9. She removed an equal number of brown marbles and silver marbles from the bag. The ratio of the number of brown marbles and silver marbles left in the bag became 5 : 1. What percentage of the marbles were left in the bag?
|
Brown marbles |
Silver marbles |
Difference |
Total |
Before |
16x4 = 64 u |
9x4 = 36 u |
7x4 = 28 u |
25x4 = 100 u |
Change |
- 29 u |
- 29 u |
|
|
After |
5x7 = 35 u |
1x7 = 7 u |
4x7 = 28 u |
6x7 = 42 u |
When Yoko removed an equal number of brown marbles and silver marbles, the difference between the number of brown marbles and silver marbles at first and in the end remains the same.
LCM of 7 and 4 is 28.
Percentage of the marbles left in the bag
=
42100 x 100%
= 2150 x 100%
= 42%
Answer: 42%