1.  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. ?
A. 8 kmph
B. 11 kmph
C. 12 kmph
D. 14 kmph

Answer: Option C

Explanation:

Let the distance travelled be x km.
Then, x/10 - x/15 = 2
<=> 3x - 2x = 60
<=> x = 60 km

Time taken to travel 60 km at 10 km/hr :
= 60/10 hrs
= 6 hrs.

So, Robert started 6 hours before 2 P.M. i.e., at 8 A.M.

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