Answer
$v_{avg}=6.5\frac{Km}{s}$
Work Step by Step
We know that the average speed can be calculated as
$v_{avg}=\frac{\Sigma v}{N}$
where $\Sigma v$ shows the sum of speeds of all the molecules and $N$ is the total number of molecules.
The total number of molecules $N$ is 10. We substitute the values of $v$ and of $N$ into the formula to solve:
$v_{avg}=\frac{2+3+4+5+6+7+8+9+10+11}{10}$
$v_{avg}=6.5\frac{Km}{s}$
