PSLE A box contained green balls and grey balls. 40% of the balls were grey. After some brown balls were added to the box, 38% of the balls were grey. What percentage of the balls in the box were brown?
|
Grey |
Green |
Brown |
Total |
Before |
2 u |
3 u |
|
5 u |
Change |
|
|
+ ? |
|
After |
38% |
57% |
|
100% |
40% =
40100 =
25 The number of grey balls remains unchanged.
2 u → 38%
1 u → 38% ÷ 2 = 19%
3 u → 3 x 19 = 57%
Percentage of the balls in the box that were brown
= 100% - 38% - 57%
= 5%
Answer(s): 5%