Assuming that the energy transfer efficiency between trophic levels is 10%, how much grain would be required to produce 70 kg of human biomass if the grain is eaten by cows and the cows are eaten by humans?

According to Lindermann's law of 10 per cent energy transfer, there is a gradual decrease of 10 per cent in the energy flow across the food chain. To produce 70 kg of human biomass, 7000 kg must be produced by plants, which are eaten by cows. The cows will have a decrease in 10 per cent energy, now having 700 kg of biomass, which are in turn eaten by man. The man will finally have the 70kg biomass required.