Question

Robert is travelling on his cycle and has calculated to reach point A at 2 P.M. 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 P.M.?

Answer 1

The answer is 12 kmph.

Solution:-

Let the distance traveled be x km.

According to question,
(x/10) - (x/15) = 2
=>3x - 2x = 60
=>x = 60 km

Now,time taken to travel 60 km at 10 km/hr = 60/10 hrs =6 hrs
So, Robert started 6 hours before 2 P.M. i.e., at 8 A.M.

Difference between 8 am to 1 pm is 5 hrs.
Therefore,required speed = 60/5 kmph. = 12 kmph

Answer 2

At 12 kmph speed must he travel to reach A at 1 P.M.

BECAUSE.....

Let the distance travelled by x km.
Then,x/10-x/15= 2
 3x - 2x = 60
 x = 60 km.
time taken to travel 60 km at 10 km/hr =60/10hrs= 6 hrs.
So, Robert started 6 hours before 2 P.M. i.e., at 8 A.M.

Required speed =60/5kmph.= 12 kmph.