Answer
$15s$
Work Step by Step
We can find the required time as follows:
$t=\frac{4mL_f}{K\pi d^2(\frac{T_{cylinder}-T_{ice}}{L})}$
We plug in the known values to obtain:
$t=\frac{4(25g(\frac{1Kg}{1000g}))(33.5\times 10^4J/Kg)}{390W/m.C^{\circ}\pi(0.75m)^2}(\frac{120C^{\circ}-0.0C^{\circ}}{0.37m})$
This simplifies to:
$t=15s$
