A motorcyclist at a speed of 30 km / h catches up with a cyclist moving in front of him. After what time

A motorcyclist at a speed of 30 km / h catches up with a cyclist moving in front of him. After what time, the motorcyclist will catch up with the cyclist, if the cyclist’s speed is 12 km / h and the distance between the motorcycle and the cyclist at the moment of starting the motorcycle was 72 km.

Let the motorcyclist catch up with the cyclist in x hours. During this time, a cyclist will travel 12 * x km, and a motorcyclist 30 * x km.
Let’s make the equation:
30 * x = 12 * x + 72.
30 * x – 12 * x = 72.
18 * x = 72.
x = 4 hours.
Answer: The motorcyclist will catch up with the cyclist in 4 hours.