trigeminal

The answer is 10.6 and explained well by genius. All the answer choices are wrong and are against logic as they are more than the speed of passenger train and hence overtaking is impossible!!

B Total time required- (1400x15)+(420x20)=29400min Total time available- 7x60 = 420min No of persons required=29400/420 = 70 persons (easy to calculate after omitting zeroes)