Question

A train travels the first 15 km at a uniform speed of 30 kmh-1, the next 75 km at a
uniform speed of 50 kmh-1, and the last 10 km at a uniform speed of 20 kmh 1.​

Answer 1

Explanation:

Answer

Given,

d

1

=15km,v

1

=30km/h

d

2

=75km,v

2

=50km/h

d

3

=10km,v

3

=20km/h

we know that,

average speed =total distance covered/total time taken

total distance covered =D=15+75+10=100km

total time taken =T=(15/30)+(75/50)+(10/20)=2.5hours

so, average speed =100/2.5=40km/h