Maths : Time, Speed & Distance

Maths :: Time, Speed & Distance

Points to remember:

1. To find Distance  =  Speed  x  Time

2. To find Speed     =   Distance divided by Time

3. To find Time       =   Distance divided by Speed

4.  1 km / per hr      =   5/18 m / per second

    [ i.e., to convert given speed @ km per hour 

             into speed @ metre per second,

             multiply it by 5/18 ]

5.  1 m / per sec      =  18/5 km / per hour

      [ i.e., to convert given speed @ metre per second

               into speed @ km per hour,

               multiply it by 18/5 ]

6. If 'a' is onward journey speed, and 'b' is return journey speed, 

    then the average speed in a travel between two stations, then

    the average speed for the whole journey would be

        2 multiplied by 'a and by 'b'

        divided by 'a' + 'b'

           i.e.,    2ab divided by (a + b)

7. If a boy walks from his house to school at the rate of 5 kmph, and 

    reaches the school 10 minutes earlier than the scheduled time, and 

    if he walks at the rate of 3 kmph , he reaches 10 minutes late, 

    then the distance of the school from his house  would be:

    Distance covered = Product of Two Speeds x Diff. in Time

                                    divided by Diff of Two Speeds x 60

  and so, the answer = 5 x 3 x (10 + 10)

                                  divided by  2 x 60 = 2.5 km