PSLE A box contained silver beads and gold beads. 30% of the beads were gold. After some black beads were added to the box, 12% of the beads were gold. What percentage of the beads in the box were black?
|
Gold |
Silver |
Black |
Total |
Before |
3 u |
7 u |
|
10 u |
Change |
|
|
+ ? |
|
After |
12% |
28% |
|
100% |
30% =
30100 =
310 The number of gold beads remains unchanged.
3 u → 12%
1 u → 12% ÷ 3 = 4%
7 u → 7 x 4 = 28%
Percentage of the beads in the box that were black
= 100% - 12% - 28%
= 60%
Answer(s): 60%