A man whose mass is $60\,kg$ is standing in the rear end of a platform whose mass is $140\,kg$ which is moving with no friction over an ice rink with a velocity of $4\,\hat{i}\,\frac{m}{s}$. The man moves with a speed of $2\,\frac{m}{s}$ with respect to the platform. Find the speed of the platform with respect to the ground in $\frac{m}{s}$.

The alternatives given are as follows:

$\begin{array}{ll}

1.&-4.6\,\hat{i}\,\frac{m}{s}\\

2.&-3.4\,\hat{i}\,\frac{m}{s}\\

3.&2\,\hat{i}\,\frac{m}{s}\\

4.&3.4\,\hat{i}\,\frac{m}{s}\\

5.&4.6\,\hat{i}\,\frac{m}{s}\\

\end{array}$

The only thing which I could find was the speed of the man:

v_man-v_platform = 2

v_man=2+v_platform = 2+ 4 = 6

But I'm not sure how to relate the other given information. Can someone help me here?.