Analysis of Frequency Distributions

If the coefficients of variation of two distributions are $40$ and $20$ and their variances are $144$ and $64$ respectively, then the mean of their arithmetic means is

What is the formula for finding co-efficient of variation, given $\sigma =$ standard deviation and $\overline{x}=$mean $\ne 0?$

The temperature of two cities $A$ and $B$ in a winter season are given in the table.

Find which city is more consistent in temperature changes?

Coefficient of variation = $\frac{SD}{Mean}\times$_____