Question

Two bicycles start from two different points on a straight road. The first bicycle travels at a constant speed of 18 km/h towards the east while the second bicycle travels at a constant speed of 12 km/h. Towards the west if the two bicycles start at the same time from a point that is 36km/h away from each other, how long does it take to cross each other at what distance from each starting point?

Answer 1

Let's assume the distance from the starting point to where the bicycles cross each other is x km from the first bicycle's starting point.

The first bicycle is traveling at a speed of 18 km/h towards the east, so its distance covered in time t is 18t km.

The second bicycle is traveling at a speed of 12 km/h towards the west, so its distance covered in time t is 12t km.

Since the two bicycles started at the same time, their total distance covered is the sum of their distances covered individually. This is given by:
18t + 12t = 36
30t = 36
t = 36/30
t = 6/5 hours

To find the distance from each starting point, we can substitute the value of t in either of the two equations. Let's use the equation for the distance covered by the first bicycle:
Distance covered by the first bicycle = 18*t
Distance covered by the first bicycle = 18 * (6/5)
Distance covered by the first bicycle = (18 * 6)/5
Distance covered by the first bicycle = 108/5 km

Therefore, it would take 6/5 hours (or 1.2 hours), for the bicycles to cross each other. The distance from the first bicycle's starting point to where they cross is approximately 21.6 km.