A plane flew over point a at a speed of 300 km / h in 1 hour, 2 aircraft flew in the same direction

A plane flew over point a at a speed of 300 km / h in 1 hour, 2 aircraft flew in the same direction at a speed of 400 km / h.

Data: Vс1 – speed of the first aircraft (Vс1 = 300 km / h); Δt is the difference between the start of flights (Δt = 1 h); Vс2 – speed of the second aircraft (Vс2 = 400 km / h); S – distance to point B (S = 1200 km).

1) The duration of the flight of the first aircraft: tc1 = S / Vc1 = 1200/300 = 4 hours.

2) The duration of the flight of the second aircraft: tc2 = S / Vc2 = 1200/400 = 3 hours.

3) Time of arrival: tпр1 = tс1 = 4 hours and tпр2 = tс2 + Δt = 3 + 1 = 4 hours (simultaneous arrival).

Answer: The planes must arrive at point B at the same time.