find out the rate of selling price per unit if 20 profit on sale price is desired as 619592

A work order for 500 units of a commodity has to pass through four different machines, the machine hour rates of which are:

The following expenses have been incurred on the work order:

Materials Rs. 20,000; Wages Rs. 1,500

Machine 1 worked for 200 hours

Machine 2 worked for 300 hours

Machine 3 worked for 240 hours

Machine 4 worked for 100 hours

After the work order has been executed, materials worth Rs. 1,000 were returned to stores.

Office overheads are to be estimated at 60% of works cost; 10% of the production is going to be discarded, being unsatisfactory for which ½ of the cost can be realized from sale in the scrap market.

Find out the rate of selling price per unit if 20% profit on sale price is desired. Assume the net result output is 500 units.