1. The problem statement, all variables and given/known data Eighty per cent of all scheduled trains through Roma Street station arrive on time. If 10 trains go through the station every day, find: a the probability that at least 8 trains are on time b the probability that at least 8 trains are on time for 9 out of the next 10 days. 2. Relevant equations P(X = x) = nCxpxqn − x 3. The attempt at a solution P(X>=8) n=10 x=8+9+10 p=0.8 q=0.2 P(X=8)+p(X=9)+p(X=10) = 0.6778 10C80.880.22 +10C90.890.21+10C100.8100.20 b I guess I would use: P(X=8)+p(X=9)+p(X=10) = 0.6778 But I am not sure how. Please help!