Question

The mean of a data is 15 and the sum of the observations is 195. The number of observations is

(a) 13 (b) 19 (c) 16 (d) 17

Answer 1

Mean of data = 15
Sum of observations = 195
$$\begin{gathered} \mathrm{Mean}=\frac{\mathrm{Sum}\mathrm{of}\mathrm{observations}}{\mathrm{Number}\mathrm{of}\mathrm{observations}\left(n\right)} \\ \Rightarrow 15=\frac{195}{n} \\ \Rightarrow n=\frac{195}{15}=13 \end{gathered}$$
Thus, the number of observations is 13.
Hence, the correct option is (a).