PSLE A box contained white balls and purple balls. 60% of the balls were purple. After some grey balls were added to the box, 57% of the balls were purple. What percentage of the balls in the box were grey?
|
Purple |
White |
Grey |
Total |
Before |
3 u |
2 u |
|
5 u |
Change |
|
|
+ ? |
|
After |
57% |
38% |
|
100% |
60% =
60100 =
35 The number of purple balls remains unchanged.
3 u → 57%
1 u → 57% ÷ 3 = 19%
2 u → 2 x 19 = 38%
Percentage of the balls in the box that were grey
= 100% - 57% - 38%
= 5%
Answer(s): 5%