The average mass of 20 bricks increases by 0.5 kg when a stone is placed in place of one of the bricks having mass 3 kg. What might be the mass of the stone?

Correct option is B

The average mass of 20 bricks increases by 0.5 kg when a stone is placed in place of one of the bricks having mass 3 kg. the mass of the stone is 13 kg