PSLE A box contained red beads and silver beads. 70% of the beads were silver. After some grey beads were added to the box, 49% of the beads were silver. What percentage of the beads in the box were grey?
|
Silver |
Red |
Grey |
Total |
Before |
7 u |
3 u |
|
10 u |
Change |
|
|
+ ? |
|
After |
49% |
21% |
|
100% |
70% =
70100 =
710 The number of silver beads remains unchanged.
7 u → 49%
1 u → 49% ÷ 7 = 7%
3 u → 3 x 7 = 21%
Percentage of the beads in the box that were grey
= 100% - 49% - 21%
= 30%
Answer(s): 30%