PSLE Shannon had a box of brown marbles and white marbles in the ratio 16 : 9. She removed an equal number of brown marbles and white marbles from the box. The ratio of the number of brown marbles and white marbles left in the box became 10 : 3. What percentage of the marbles were left in the box?
|
Brown marbles |
White marbles |
Difference |
Total |
Before |
16x1 = 16 u |
9x1 = 9 u |
7x1 = 7 u |
25x1 = 25 u |
Change |
- 6 u |
- 6 u |
|
|
After |
10x1 = 10 u |
3x1 = 3 u |
7x1 = 7 u |
13x1 = 13 u |
When Shannon removed an equal number of brown marbles and white marbles, the difference between the number of brown marbles and white marbles at first and in the end remains the same.
LCM of 7 and 7 is 7.
Percentage of the marbles left in the box
=
1325 x 100%
= 1325 x 100%
= 52%
Answer: 52%