A,B,C are three persons amongst seven persons who speak at a function. The number of ways in which it can be done if A speaks before B and B speaks before C is
The metro service has a train going from Mumbai to Pune and Pune to Mumbai every hour, the first one at 6 a.m. The trip from one city to other takes 4 and half hours. and all trains travel at the same speed. how many trains will you pass while going from Mumbai to Pune if you start at 12 Noon?