(1) According to the meaning of the question, a=0.04×5×800= 160, b=0.02×5×800=80,

(2) If the number of students who won the first prize is X, then x80=40800 and x=4, that is, the number of students who won the first prize is 4.

(3) According to the meaning of the question, the possible value of x is 0, 1, 2.

P(X=0)=C236C240=2 126，P(X= 1)=C 136？ C 14C240= 1265，P(X = 2)= c24c 240 = 1 130，

So the distribution list of x is:

x 0 1 2p 2 126 1265 1 130 ex = 0×2 126+ 1× 1265+2× 165438+