Question

Consider the frequency distribution of the given numbers.
$\begin{array}{ccccc}Value& 1& 2& 3& 4\\ Frequency& 5& 4& 6& f\end{array}$
​If the mean is known to be 3, then the value of f is:

• A. 3
• B. 7
• C. 10
• D. 14

Answer 1

The correct option is D 14

$Mean=\frac{1\times 5+2\times 4+3\times 6+4\times f}{15+f}$
$i.e.,3=\frac{5+8+18+4f}{15+f}\Rightarrow 45+3f=31+4f$
$\Rightarrow 45-31=f\Rightarrow f=14$