Word motion problems

Question

An airplane bucks a headwind of 75 kph for 4 hours and return the same distance assisted by a tailwind also 75 kph in an hour less. How long it will take to travel the same distance (one way trip) without wind?

Answer 1

Let the speed of the pla

Let speed in still air be s. Then, speed with a 75 kph tail wind is s+75, and speed with a 75 kph headwind is s-75.

As we travel 4 hours with a headwind and 3 hours with a tail wind, but the same distance in both cases,

3(s+75) = 4(s-75)

3s + 225 = 4s - 300

525 = s

Distance is (525+75)3 = 1800

Then, the time in still air is 1800/525 = 24/7 hours