PSLE A box contained purple marbles and blue marbles. 40% of the marbles were blue. After some red marbles were added to the box, 8% of the marbles were blue. What percentage of the marbles in the box were red?
|
Blue |
Purple |
Red |
Total |
Before |
2 u |
3 u |
|
5 u |
Change |
|
|
+ ? |
|
After |
8% |
12% |
|
100% |
40% =
40100 =
25 The number of blue marbles remains unchanged.
2 u → 8%
1 u → 8% ÷ 2 = 4%
3 u → 3 x 4 = 12%
Percentage of the marbles in the box that were red
= 100% - 8% - 12%
= 80%
Answer(s): 80%