A partnership firm earned net profits during the last three years ended 31st March, as follows: Rs. 17,000; Rs. 20,000; Rs. 23,000. Capital investment in the firm throughout the above-mentioned period has been Rs. 80,000. Having regard to the risk involved, 15% is considered to be fair return on the capital. Calculate value of goodwill on the basis of two years’ purchase of average super profit earned during the year above-mentioned three years.