Answer
$c=4.5\times 10^2\frac{J}{Kg K}$
Work Step by Step
We know that:
$\Delta S=mc ln\frac {T_f}{T_i}$
This can be rearranged as:
$c=\frac{\Delta S}{m\ln \frac{T_f}{T_i}}$
We plug in the known values to obtain:
$c=\frac{50}{0.364\ln \frac{380}{280}}$
$c=4.5\times 10^2\frac{J}{Kg K}$
