Question

A train travels the first 15 km at a uniform speed of 30 km/h; the next 75 km at a uniform speed of
50 km/h; and the last 10 km at a uniform speed of 20 km/h. Calculate the average speed for the entire train
journey.
◇ plz give me answer ◇​

Answer 1

Answer:

40 km\h

d1=15km s1=30km\h

d2=10km s2=20km\h

d3=75km s3=50km\h

total time taken=t1+t2+t3

=0.5+0.5+1.5=2.5

speed =distance\time

100\2.5=40km\h

Answer 2

Average speed = $\frac{total \: distance \: travelled}{total \: time \: taken}$

This is the only formula we will use for solving this numerical of physics.

Thus, for the above question,

AVERAGE SPEED = $\frac{15 + 75 + 10}{0.5 + 1.5 + 0.5}$ km/h

$= \frac{100}{2.5}$ km/h

$= 40$ km/h