PSLE A box contained black balls and blue balls. 40% of the balls were blue. After some yellow balls were added to the box, 34% of the balls were blue. What percentage of the balls in the box were yellow?
|
Blue |
Black |
Yellow |
Total |
Before |
2 u |
3 u |
|
5 u |
Change |
|
|
+ ? |
|
After |
34% |
51% |
|
100% |
40% =
40100 =
25 The number of blue balls remains unchanged.
2 u → 34%
1 u → 34% ÷ 2 = 17%
3 u → 3 x 17 = 51%
Percentage of the balls in the box that were yellow
= 100% - 34% - 51%
= 15%
Answer(s): 15%