Robel is travelling on his cycle and he calculated to reach point A at 3 p.m. if he travels at 10 kmph, he will reach there at 1 p.m. if he travels at 15 kmph. At what speed must he travel to reach A at 2 p.m.

Question: Robel is travelling on his cycle and he calculated to reach point A at 3 p.m. if he travels at 10 kmph, he will reach there at 1 p.m. if he travels at 15 kmph. At what speed must he travel to reach A at 2 p.m.

Solution:
Let the distance travelled by x km.

ATQ,
x/10 - x/15 = 2
⇒ 3x - 2x = 60
∴ x = 60

Time taken to travel 60 km at 10km/h = 60/10 hours
= 6 hours

So, Robel started 6 hours before 3 P.M. i.e., at 9 Α.Μ.

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