Related Rates (part2) $y=\sqrt{x}$ $y = \sqrt{x}$ 

a) Find $\frac{dy}{dt}$  when $x=4$ , Given $\frac {dx}{dt}=3$

I did 

$$y = x^{1/2} \implies \frac{dy}{dt} = \frac{1}{2\sqrt{x}} \frac{dx}{dt}$$ then plugged in $x=4$ and $y=3$, but I am getting wrong solution
It should be $\frac{3}{4}$ based off of the work you have shewn.
It should be $\frac{3}{4}$ based off of the work you have shewn.