PSLE Penelope had a basket of pink marbles and black marbles in the ratio 17 : 8. She removed an equal number of pink marbles and black marbles from the basket. The ratio of the number of pink marbles and black marbles left in the basket became 9 : 1. What percentage of the marbles were left in the basket?
|
Pink marbles |
Black marbles |
Difference |
Total |
Before |
17x8 = 136 u |
8x8 = 64 u |
9x8 = 72 u |
25x8 = 200 u |
Change |
- 55 u |
- 55 u |
|
|
After |
9x9 = 81 u |
1x9 = 9 u |
8x9 = 72 u |
10x9 = 90 u |
When Penelope removed an equal number of pink marbles and black marbles, the difference between the number of pink marbles and black marbles at first and in the end remains the same.
LCM of 9 and 8 is 72.
Percentage of the marbles left in the basket
=
90200 x 100%
= 920 x 100%
= 45%
Answer: 45%