Question

In covering a distance of 40 km, kamlesh takes 2 hours more than pankaj. If kamlesh doubles his speed, then he would take 1 hour less than pankaj. Then what is kamlesh's speed?

Answer 1

let time taken by pankaj be t

then time taken by kamlesh is t+2

distance =40 km

initial speed of kamles=u

final speed of kamlesh=2u

new time taken by kamlesh=t-1

u=40/t+2

or

2u=80/t+2

also

2u=40/t-1

equating the 2 equations

80/t+2=40/t-1

t=4 hr

therefore speed of kamlesh is

u=40/t+2

=40/6

=20/3 km/hr