son corporations stockholder equity at dec 31,2015

capital stock $10 per 60,000shares issued and outstanding =$600

addtional paid in capital =$150

Retained earnings = $250

Total stockholders equity =$1000

on jan 1,2016,Pop corporation purchased 20,000 previously unissued shares of son stock directly from son corporation for $500,000

a) cal pop corporation percentage ownership in son

b) determine the goodwill (if any) from pop investment in son. assume book value of all identified assets and libaility equal the fair value