Time & Distance, Trains, Boats & Streams Tricks and Formulas

Time & Distance

Suppose a man covers a distance at ‘x’ kmph and an equal distance at ‘y’ kmph, and then average speed during his whole journey is Equation kmph


  • Lengths of trains are ‘x’ km and ‘y’ km, moving at ‘u’ kmph and ‘v’ kmph Equation in the same direction, then the time taken y the over-taker train to cross the slower train is Equation hrs

  • Time taken to cross each other Equation hrs

  • If two trains start at the same time from two points A and B towards each other and after crossing they take a and b hours in reaching B and A respectively.

  • Equation

  • Equation

Boats & Streams

  • If the speed of a boat in still water is Equation and the speed of the stream is v Equation , then: Equation and Equation

  • If the speed downstream is a km/hr and the speed upstream is b km/hr, then: Speed in still water Equation . and Rate of stream Equation km/hr.