MCQ
If the mean of frequency distribution is $8.1$ and $\sum\text{f}_\text{i}\text{x}_\text{i}=132+5\text{k},\sum\text{f}_\text{i}=20,$ then $k =$
- A$3$
- B$4$
- C$5$
- ✓$6$
✓
Answer
Correct option: D.
$6$
Given : $\sum\text{f}_\text{i}\text{x}_\text{i}=132+5\text{k},\sum\text{f}_\text{i}=20$ and mean $= 8.1.$
Then $, \text{Mean}=\frac{\sum\text{f}_\text{i}\text{x}_\text{i}}{\sum\text{f}_\text{i}}$
$8.1=\frac{132+5\text{k}}{20}$
$162=132+5\text{k}$
$5\text{k}=30$
$\text{k}=6$
Hence, the correct option is $(d).$
Then $, \text{Mean}=\frac{\sum\text{f}_\text{i}\text{x}_\text{i}}{\sum\text{f}_\text{i}}$
$8.1=\frac{132+5\text{k}}{20}$
$162=132+5\text{k}$
$5\text{k}=30$
$\text{k}=6$
Hence, the correct option is $(d).$
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