Coefficient of variation of two distributions are 60 and70, and their standard deviations arc 21 and 16, respectively. The sum of their arithmetic means is
 

$\text{ Given C.V. (1st distribution) }=60,{\sigma }_1=21$

$\text{ C.V. (2nd distribution) }=70,{\sigma }_2=16$

$\text{ Let }\overline{x_1}\text{ and }\overline{x_2}\text{ be the means of }1\text{ st and }2\text{ nd distribution, }$$\text{ respectively. Then }$

$\begin{array}{r}\text{ C.V. (1st distribution) }=\frac{{\sigma }_1}{{\overline{x}}_1}\times 100\\ \text{ Therefore }\\ 60=\frac{21}{{\overline{x}}_1}\times 100\text{ or }{\overline{\overline{x}}}_1=\frac{21}{60}\times 100=35\\ \text{ And C.V. }\left(2^{\text{nd }}\text{ distribution) }=\frac{{\sigma }_2}{{\overline{x}}_2}\times 100\right.\\ \text{ i.e., }70=\frac{16}{{\overline{x}}_2}\times 100\text{ or }\overline{x_2}=\frac{16}{70}\times 100=22.85\end{array}$

      Sum of means = 35 + 22.85 =57.85