Answer
a) Peak current = $295A$
b) Peak voltage = $339V$
c) Billed energy = $3000kWh$
Work Step by Step
a) average Power = RMS voltage $\times$RMS current
Thus, RMS current = average Power / RMS voltage = $\frac{50\times10^{3}}{240}=208.3A$
Therefore, Peak current =$\sqrt 2\times208.3=295A$
b) peak Voltage = RMS voltage $\times\sqrt 2=240\sqrt 2=339V$
c) Billed energy = $50\times 1000\times 30 \times2 = 3000kWh$