Two bodies whose masses are $m_1=\,1\,kg$ and $m_2=2\,kg$ collision with speeds $v_1=1\,\frac{m}{s}$ and $v_2=\,4\,\frac{m}{s}$ as indicated in the figure from below. If the $COR$ (coefficient of restitution) is $0.2$. Find the speed in $\frac{m}{s}$ of the second body after the collision.

The alternatives given are:

$\begin{array}{ll}

1.&0.5\,\frac{m}{s}\\

2.&2\,\frac{m}{s}\\

3.&1\,\frac{m}{s}\\

4.&1.5\,\frac{m}{s}\\

5.&3\,\frac{m}{s}\\

\end{array}$

I'm lost at this problem. Can someone help me?. The only thing I can recall is that the coefficient of restitution or COR is a relationship between the kinetic energies as follows:

$COR=\frac{\textrm{K.E after the collision}}{\textrm{K.E before the collision}}$

But I don't know how to relate this to the problem in order to solve it. Can somebody help me here?.