Question

A plane left 40 minutes late due to bad weather and in order to reach its destination, 1600 km away in time, it had to increase its speed by 400 km/hr from its usual speed. Find the usual speed of the plane.

Answer 1

Given that, if speed is increased by 400 km/hr, the plane takes 40 minutes less than that of the usual time. Speed of the plane after increasing = (x + 400) km/hr

⇒ Time taken by the plane with increasing speed