Find the arithmetic mean of the following distribution    

We know that   $( \overline{x} ) = \frac{\sum f_i x_i}{\sum f_i }$

The total frequency $\sum f_i$is $=30$

$\sum f_i x_i =200$

$( \overline{x} )=\frac{200}{30}$

The mean of the given distribution is 6.66.