PSLE A box contained yellow balls and black balls. 60% of the balls were black. After some red balls were added to the box, 48% of the balls were black. What percentage of the balls in the box were red?
|
Black |
Yellow |
Red |
Total |
Before |
3 u |
2 u |
|
5 u |
Change |
|
|
+ ? |
|
After |
48% |
32% |
|
100% |
60% =
60100 =
35 The number of black balls remains unchanged.
3 u → 48%
1 u → 48% ÷ 3 = 16%
2 u → 2 x 16 = 32%
Percentage of the balls in the box that were red
= 100% - 48% - 32%
= 20%
Answer(s): 20%