THanks Isomorphism ,

My second attempt :

P(A wins ) = 2[1-P(B wins)-P(draw)]
P(A wins) = 2-2P(B wins)-2P(draw) ------ 1st equation

P(B wins)= 3P(draw) ----- 2nd equation

P(draw) = 1-P(A wins)-P(B wins ) ---- 3rd equation

But after simplifying , i got P(draw)=1/4
My answer is wrong according to the book . Did i get the equations right in the first place ? Thanks for any help ..