TIME AND DISTANCE

1.     Speed = $\frac{Distance}{Time}$

2.     Time = $\frac{Distance}{Speed}$

3.     Distance = $(Speed \times  Time)$

4.     x km/hr = $(x\times\frac{5}{18})$ m/sec

5.     x m/sec = $(x\times\frac{18}{5})$ km/hr

6.     If the ratio of speeds of A and B is a:b ,  then ratio of the times taken by them to cover the same distance is  b:a

7.     If a certain distance is covered at  x km/hr and the same distance is covered at  y km/hr , then the average speed during the whole journey
                                                               = $\frac{2xy}{x+y}$ km/hr