Answer
$840\frac{Kg}{s}$
Work Step by Step
We know that
$thrust=(\frac{\Delta m}{\Delta t})(v)=mg$
This can be rearranged as:
$\frac{\Delta m}{\Delta t}=\frac{mg}{v}$
We plug in the known values to obtain:
$\frac{\Delta m}{\Delta t}=\frac{(5300)(9.81)}{62}$
$\frac{\Delta m}{\Delta t}=840\frac{Kg}{s}$