The distance between quays M and H is 162 km. The motor ship departed from the pier M at a speed of 45 km / h

The distance between quays M and H is 162 km. The motor ship departed from the pier M at a speed of 45 km / h. After 45 minutes, another motor ship departed from the pier N at a speed of 36 km / h. How many hours after the departure of the first ship will they meet?

Let’s find the distance covered by the first motor ship in 45 minutes (3/4 hours):
45 * (3/4) = 33.75 km.
Then the remaining distance is:
162 – 33.75 = 128.25 km
Since the ships were moving towards a meeting, the approach speed is equal to the sum of the speeds:
45 + 36 = 81 km / h
Then travel time before the meeting:
128.35: 81 = 1.58 hours, or relative to the first:
1.58 + 0.75 = 2.33 = 2 hours 20 minutes.