PSLE A box contained black marbles and red marbles. 60% of the marbles were red. After some brown marbles were added to the box, 33% of the marbles were red. What percentage of the marbles in the box were brown?
|
Red |
Black |
Brown |
Total |
Before |
3 u |
2 u |
|
5 u |
Change |
|
|
+ ? |
|
After |
33% |
22% |
|
100% |
60% =
60100 =
35 The number of red marbles remains unchanged.
3 u → 33%
1 u → 33% ÷ 3 = 11%
2 u → 2 x 11 = 22%
Percentage of the marbles in the box that were brown
= 100% - 33% - 22%
= 45%
Answer(s): 45%