# Time, Speed And Distance

**Speed, Distance & Time**

• Speed = distance/time

• Time = distance/ Speed

• Distance = (Speed * Time)

• Distance = Rate x Time

• Rate = Distance/Time

• Convert from kph (km/h) to mps(m/sec): x km/hr=x∗(5/18) m/sec

• Convert from mps(m/sec) to kph(km/h): x m/sec= X*(18/5) km/h

• If the ratio of the speeds of A and B is a : b,

then the ratio of the times taken by then to

cover the same distance is :1/a : 1/b or b:a

• Suppose a man covers a certain distance at x

km/hr and an equal distance at y km/hr.

Then, the average speed during the whole journey

is :- 2xy/(x + y)

• When speed is constant distance covered by

the object is directly proportional to the time

taken. ie; If S_{1}=S_{2} then D_{1}/D_{2} = T_{1}/T_{2}

• When time is constant speed is directly

proportional to the distance travelled. i.e; If

T_{1}=T_{2} then S_{1}/S_{2}=D_{1}/D_{2}

• When distance is constant speed is inversely

proportional to the time taken i.e if speed

increases then time taken to cover the

distance decreases. ie; If D_{1}=D_{2} then S_{1}/S_{2}

= T_{2}/T_{1}

• If the speeds given are in Harmonic

progression or HP then the corresponding

time taken will be in Arithmetic progression

or AP

• If the speeds given are in AP then the

corresponding time taken is in HP

• If two objects are moving in same direction

with speeds a and b then their relative speed

is |a-b|

• If two objects are moving is opposite direction

with speeds a and b then their relative speed

is (a+b)

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