Question

A person covered the distance from P to Q at a speed
of 40 kmph. He covered three-fifths of the distance in
two-thirds of the total time. At what speed (in kmph)
should he travel to complete the remaining part of the
journey in the remaining time?​

Answer 1

3/5d=40km/h×2/3t
3/5d=80d/3
d=80/3,
remaining time is 1/3
speed =d/t
80/3÷1/3
is 80 km/h

Answer 2

The remaining part of the journey should be traveled in 4 km/hr.

Step-by-step explanation:

Let the distance covered be 'x'.

Let the time be 't'.

So, if speed = 40 km/hr

So, it becomes,

$speed=\dfrac{x}{t}=40\\\\x=40t$

if distance covered three fifths of the distance would be

$\dfrac{3x}{5}$

Time would be

$\dfrac{2t}{3}$

So, Required speed would be

Total speed - used speed for above distance

$\dfrac{x}{t}-\dfrac{3x\times 3}{5\times 2t}\\\\=\dfrac{x}{t}-\dfrac{9x}{10t}\\\\=\dfrac{10x-9x}{10t}\\\\=\dfrac{x}{10t}$

now, put the value of x in the above equation,

$\dfrac{40t}{10t}=4\ km/hr$

Hence, the remaining part of the journey should be traveled in 4 km/hr.

# learn more:

A person travels for 3 hours at the speed of 40 kmph and for 4.5 hours at the speed of 60 kmph. At the end of it, he finds that he has covered (3/5)th of the total distance. At what average speed should he travel to cover the remaining distance in 4 hours?

https://brainly.in/question/5209726