A lorry-load of materials of mixed goods were purchased for Rs. 90,000. These were sorted into the following grades whose market rate is shown against each:

Grade A – 5,000 units selling rage @ Rs. 12 Grade B – 3,000 units selling rage @ Rs. 10 Grade C – 2,000 units selling rage @ Rs. 5 Find the purchase rate per unit on each grade of the material assuming that all grades yield same rate of profi t.