at Rs. 60/unit the demand facing the dominant firm will be zero. When price falls to Rs. 50/unit, total market demand increases from 30 units to 40 units, but aggregate supply of ten suppliers reduces from 30 units to 20 units, causing a shortfall of supply by 20 units. This {(40 – 20) units =} 20 units is the demand for the dominant firm’s product.