PHYSICS - HELP ME PLEASE!!!!!!!!!!!!!!?

Question

A heat engine operating between energy reservoirs at 20 DEGREES C and 600 degrees c has 30% of the maximum possible efficiency.

How much energy must this engine extract from the hot reservoir to do 1000 J of work?

Answer 1

The maximum possible efficiency = T hot / (T hot - T cold)

600 C / ( 600 C - 20 C ) = 1.034482759

30% of the maximum possible efficiency = 0.3 * 1.034482759 = 0.310344828

eff = Q hot / W

Hot reservoir energy (Q hot) = ?

Work (W) = 1000 J

Q hot = eff * W = 0.310344828 / 1000 J = 3.10E-04 J