Question

2. A train covers half of its journey with a speed of 36km/h and
other half with a speed of 54km/h. calculate its average speed for
the entire journey?

Answer 1

Answer:

45km/hr

x+y/2

36+54/2=45km/hr

Answer 2

Question

• A train covers half of its journey with a speed of 36km/h and other half with a speed of 54km/h. calculate its average speed for the entire journey

Given

• A train cover half of its journey with a speed of 36km/h and rest journey with a speed of 54 km/h $\sf$

Find

• Average speed and total distance ?

Solution

★ Average speed = Total distance ÷ Total time

Let,

• The total distance be “ d ”

• The train covers distance d/2 at 36 m/s

So ,

• the time taken for this half of the journey is t1 = (d/2)/36

Similarly,

• t2 = (d/2)/54

★ Total time = t1 + t2

Total time = (d/2)/36 + (d/2)/54

Total time = ( d/72 + d/108 ) { taking l.c.m }

Total time = ( 3d + 2d / 216 )

Total time = ( 5d/216)

Hence,

Average speed = Distance / time

Average speed = d / 5d/216

Average speed = 216/5

Average speed = 43.2 km/h