ANS-I C, let four balls be A,B,C,&D.; S (A+B+C+D)/4 = 20;
now the median weight of the balls is 20 , so B+C?)/2=20 i.e. B+C=40 and A+D= 40, and as per the second statement no ball weighs 20 pounds hence...from above two eqns we can safely say that by combining two statements...we...