PSLE Vanessa had a box of pink marbles and purple marbles in the ratio 16 : 9. She removed an equal number of pink marbles and purple marbles from the box. The ratio of the number of pink marbles and purple marbles left in the box became 5 : 1. What percentage of the marbles were left in the box?
|
Pink marbles |
Purple 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 Vanessa removed an equal number of pink marbles and purple marbles, the difference between the number of pink marbles and purple marbles at first and in the end remains the same.
LCM of 7 and 4 is 28.
Percentage of the marbles left in the box
=
42100 x 100%
= 2150 x 100%
= 42%
Answer: 42%