Question

000
8. A train travels first 300 km at an average rate of 30
km per hour and further travels the same distance at
an average rate of 60 km per hour, then the average
speed over the whole distance is
(A) 35 km per hour (B) 40 km per hour
(C) 42 km per hour (D) 45 km per hour
​

Answer 1

Answer:

40km per hr

Explanation:

Case 1

time taken=300/30 =10hr

Case 2

time taken =300/60 =5hr

Now

average speed =total distance/total time taken

=600/(10+5)

=600/15

=40 km per hr

Answer 2

Answer:

in first case

time =dis/speed=300/30=10hour

in second case

time =300/60=5hrs

total time taken =10+5=15hrs

total distance =300+300=600kms

avg speed =dis/time=600/15=40kmph

Explanation:

(B) is the right answer