Question

If the mean of n observations is 12 and the sum of the observations is 132, then the value of n is

(a) 9 (b) 10 (c) 11 (d) 12

Answer 1

Mean of n observations = 12
Sum of observations = 132
$$\begin{gathered} \mathrm{Mean}=\frac{\mathrm{Sum}\mathrm{of}\mathrm{observations}}{\mathrm{Number}\mathrm{of}\mathrm{observations}} \\ \Rightarrow 12=\frac{132}{n} \\ \Rightarrow n=\frac{132}{12}=11 \end{gathered}$$
Thus, the value of n is 11.
Hence, the correct option is (c).