How to calculate goodwill?

Shubham kumar (.) (620 Points)

02 December 2012  
A and B are partners Profit and Losses in ratio 3:2. C is admitted for 1/5Th share and brings Rs.10,000 As capital and necessary amount For his share of goodwill. The goodwill of entire firm is valued Rs.40,000. . . Goodwill brought by C is? plz explain.