On 1st April 2014, a firm had assets of rs. 100000 excluding stock of rs. 20000. Partner's capital accounts showed a balance of rs. 60000. The current liabilities were rs. 10000 and the balance constituted the reserve. If the normal rate of return is 8% the goodwill of the firm is valued at rs. 60000 at four years purchase of super profit. Find the average profit of the firm.