Consider a food chain Grass - goat -tiger . If the tiger has 30 j of the energy available in this food chain . How much energy was orginally available for grass . Why ?

Goat will have = (30x10) = 300J

Grass will have = (300x10) = 3000J

But Grass absorbs only 1% of total solar energy falling on its leaves.

Hence total energy (solar) available to grass = (3000 x 100) = 300,000 J