question_answer

The mean of \[{{x}_{1}}\] and \[{{x}_{2}}\] is\[{{M}_{1}}\] and that of \[{{X}_{1}},{{X}_{2}},{{X}_{3}}....\,{{X}_{4}}\]is \[{{M}_{2}}\], then the mean of \[a{{X}_{1}},a{{X}_{2}},\frac{{{x}_{3}}}{a},\frac{{{x}_{4}}}{a}\]is

A)  \[\frac{{{M}_{1}}+{{M}_{2}}}{2}\]           

B)         \[\frac{a{{M}_{1}}+\left( \frac{{{M}_{2}}}{a} \right)}{2}\]

C)  \[\frac{1}{2a}[({{a}^{2}}-1){{M}_{1}}+2{{M}_{2}}]\]  

D)  \[\frac{1}{2a}[2({{a}^{2}}-1){{M}_{1}}+{{M}_{2}}]\]