Question

The mean of $x_1+x_2+...+x_n$ is M. When $x_i,i$=1,2,....,10, is replaced by $x_i+10$, the mean is $M_1$. Then $M_1$=

• A. M
• B. M+10
• C. 10M
• D. M+100

Answer 1

Answer: (B)

M+10

$\frac{x_1+x_2+x_3+\cdot \cdot \cdot +x_{10}}{10}=M$
$\therefore \frac{x_1+10+x_2+10+x_3+10+\cdot \cdot \cdot +x_{10}+10}{10}=\frac{x_1+x_2+x_3+\cdot \cdot \cdot +x_{10}+100}{10}$
=$\frac{x_1+x_2+x_3+\cdot \cdot \cdot +x_{10}}{10}+\frac{100}{10}$
$=M+10$

'