I don't understand the first solution given in the examiners report for the above question, snippet shown below: Going from line 2 to 3 it looks as if 1) Prob(S_1<2x) has been calculated in the first integral as opposed to Prob(S_1>2x) 2) there should be a -0.5(sigma^2) term also subtracted from inside the Phi function Any help appreciated!
