PSLE A box contained black marbles and red marbles. 60% of the marbles were red. After some purple marbles were added to the box, 42% of the marbles were red. What percentage of the marbles in the box were purple?
|
Red |
Black |
Purple |
Total |
Before |
3 u |
2 u |
|
5 u |
Change |
|
|
+ ? |
|
After |
42% |
28% |
|
100% |
60% =
60100 =
35 The number of red marbles remains unchanged.
3 u → 42%
1 u → 42% ÷ 3 = 14%
2 u → 2 x 14 = 28%
Percentage of the marbles in the box that were purple
= 100% - 42% - 28%
= 30%
Answer(s): 30%