Question

Arun is travelling on his cycle and will reach point a at 2 pm if he travels at 10 kmph. he will reach there at 12 noon if he travels at 15 kmph. at what speed must he travel to reach a at 1 pm?

Answer 1

let the distance travelled be d
and time taken is t
d/10= t...........1
d/15 = t-2..........2
substract equation 2nd from 1st
d/10-d/15= t-(t-2)
d(1/10-1/15)= 2
d= 60 km
t= d/10= 60/10= 6 hrs that is at 2pm
to reach at 1pm that is in 5 hours
speed = 60/5 = 12 kmph