Introduction
Importance: Normally 1 or 2 questions on Time and dance are always asked in different of questions competitive exams.
Scope of questions: In such questions, average time/average time taken to cover any distance, Scope ratio between speeds or taken times by two persons/ distance things are asked. Other questions include questions based -reaching at some place before or after scheduled time, covering a part of distance on foot or on different Coveyances.
Way to success: In such questions concentrate on basic concepts - make 'Mind Map' and some time used Tricks as explained.
RULE 1: Distance = Speed x Time
Speed = , Time =
1 m/s = km/h , 1km/h = m/s
RULE 2: If a man travels different distances d1,d2,d3, …. And so on in different time t1,t2,t3 respectively then.
Average speed =
=
RULE 3: If a bus travels from A to B with the speed km/h and returns from B to A with the speed y km/h.then the average speed will be
RULE 4: If an object increases/decreases its speed from x km/hr. to cover a distance in will begiven.
Distance = x
Or, Distance
= x ( Change in time)
RULE 5: If an object travels certain distance with the speed of of its destination ‘t’ hopurs or after, then the taken time by object travelling at original speed is
Time = x time ( in hour)
RULE 6: Speed (s) = s
S1t1 = s2t2 ( Provided distance is constant)
RULE 7: If both objects run in opposite direction then, Relative speed = Sum of speeds.
If both objects run in the same direction then, Relative speed= Different of Speeds.
Time taken in meeting =
RULE 7: If any one overtakes or follows another, then time taken to catch
=
Or meet =
Total travelled distance to catch the thief
=