“The 10% rule”: when moving from one trophic level to another, 90% of the energy is dissipated. Using the “10% Rule”

“The 10% rule”: when moving from one trophic level to another, 90% of the energy is dissipated. Using the “10% Rule”, calculate the weight of wheat (in kg) that one owl weighing 150 g will save by eating a pest – a vole.

Let’s compose a food chain, starting from producers: wheat → vole → owl
Knowing that the mass of an owl is 150 g, and this number should be 10 times less than the mass of the previous link in the trophic chain, we can easily find the mass of the previous link 150 * 10 = 1500 and the next link (wheat) 1500 g * 10 = 15000 g = 15 kg