PSLE Natalie had a bag of gold balls and purple balls in the ratio 17 : 8. She removed an equal number of gold balls and purple balls from the bag. The ratio of the number of gold balls and purple balls left in the bag became 7 : 1. What percentage of the balls were left in the bag?
|
Gold balls |
Purple balls |
Difference |
Total |
Before |
17x2 = 34 u |
8x2 = 16 u |
9x2 = 18 u |
25x2 = 50 u |
Change |
- 13 u |
- 13 u |
|
|
After |
7x3 = 21 u |
1x3 = 3 u |
6x3 = 18 u |
8x3 = 24 u |
When Natalie removed an equal number of gold balls and purple balls, the difference between the number of gold balls and purple balls at first and in the end remains the same.
LCM of 9 and 6 is 18.
Percentage of the balls left in the bag
=
2450 x 100%
= 1225 x 100%
= 48%
Answer: 48%