PSLE A box contained yellow balls and brown balls. 70% of the balls were brown. After some pink balls were added to the box, 21% of the balls were brown. What percentage of the balls in the box were pink?
|
Brown |
Yellow |
Pink |
Total |
Before |
7 u |
3 u |
|
10 u |
Change |
|
|
+ ? |
|
After |
21% |
9% |
|
100% |
70% =
70100 =
710 The number of brown balls remains unchanged.
7 u → 21%
1 u → 21% ÷ 7 = 3%
3 u → 3 x 3 = 9%
Percentage of the balls in the box that were pink
= 100% - 21% - 9%
= 70%
Answer(s): 70%