PSLE A box contained brown marbles and pink marbles. 60% of the marbles were pink. After some black marbles were added to the box, 54% of the marbles were pink. What percentage of the marbles in the box were black?
|
Pink |
Brown |
Black |
Total |
Before |
3 u |
2 u |
|
5 u |
Change |
|
|
+ ? |
|
After |
54% |
36% |
|
100% |
60% =
60100 =
35 The number of pink marbles remains unchanged.
3 u → 54%
1 u → 54% ÷ 3 = 18%
2 u → 2 x 18 = 36%
Percentage of the marbles in the box that were black
= 100% - 54% - 36%
= 10%
Answer(s): 10%