A geyser heats water flowing at a rate of 2.0 kg per minute from 30°C to 70°C. If geyser operates on a gas burner, the rate of combustion of fuel will be ____________g min–1 [Heat of combustion = 8 × 10³ Jg⁻¹ Specific heat of water = 4.2 Jg–1 °C⁻¹]