Question

Q3. On a 120 km track, a train travels the first 30 km with a uniform
speed of 30 kmph. How fast must the train travel the next 90 km so as to
average 60 kmph for the entire trip?

Answer 1

Answer:

Step-by-step explanation:Average speed=Total distance Total time taken

V /av

​

=

t/d

​

ort=

V /av

​

d

​

For 120 km,

t=

60 km/hr

120 km

​

=2 hr .....

.(i)

For 1st 30 km,

t /1

​

=

30 km/hr

30 km

​

=1 hr

For remaining 90 km,

t /2

​

=t−t

1

​

=2−1=1 hr

speed=

time

distance

​

 or v

2

​

=

t /2

​ d /2

​  =

1

90

​

=90 km/hr