answer,,,,,,, cpt exam june -2010

Hello,

     Follwing qusation Iam confused please given me answer

1)     When 10 units goods the price is 200 and when the goods is 20 price is 600 in that what will be marginal cost  ?

      A) 400   B) 200   C) 40   D) None of these

     ( This qusation in exam said that marginal cost of good not merely for one unit in that case what will be marginal cost )    

 2) please given me answer what measer of ogive curve median or quartiles or both .

        ( in mastermind paper there are given ogive curve measer both median and qurtiles but according  to maths teacher it is only mediam can this is correct answer or not )             

 3 ) Which of the following not feature of the Imperpect competation ?

                 A) Homogenous product  B) Price differtion C) Few seller  D) Price War

      ( In that qusation some students given answer is homegenous product but my qusation is when in imperpect competation there are produced homegenous goods and there is non- price competation then what basis of answer is homogenous product in imperpect competation the feature are produced homegenous or diffention product and ther firm takes no price war because when any firm increse or decrese price the firm also risk of go outside competation please any suggation please post here)

   4)  Variance of  standered normal distrubution is----------

        A)  0   B) 1    C) μ   D)  σ²

 ^{( This qusation answer some was given option numer D and some given 1 please give correct exactely what answer of that )}