One very handy electrical formula is
Power dissipated by a resistance = (Voltage)²/(resistance) .
24 kilowatts = (240 v)² / Resistance
Multiply each side by (Resistance):
(Resistance) x (24 kilowatts) = (240 v)²
Divide each side by (24 kilowatts):
Resistance = (240 v)² / (24,000 watts)
Resistance = (57,600 / 24,000) (volt² / volt · Amp)
Resistance = 2.4 (volt/Amp)
Resistance = 2.4 Ohms