Question

An airplane took 2 hours to fly 600 km against a head wind. The retrun trip with the wind took 1 and two thirds hours. Find the speed of the plane in stll air.

Answer 1

Answer:

The speed of plane in still air is 330 kmph  

Step-by-step explanation:

Given as :

The distance cover against the wind = 600 km

The time taken against the wind = 2 hours

The distance cover with the wind = 600 km

The time taken with the wind =  ( 1 + $\frac{2}{3}$ ) hours

                                                =  $\frac{5}{3}$ hours

Let The speed against the wind  = x - y  kmph

The speed with the wind = x + y  kmph

where x is the speed of plane in still air

And y is the speed of wind

So , Speed = $\dfrac{\texrm Distance}{\texrm Time}$

Or, x - y = $\frac{600}{2}$ = 300         ......A

And x + y = $\frac{600}{\frac{5}{3} }$

Or , x + y = 360                                                 .......B

From eq A and B

( x + y ) - ( x - y ) = 360 - 300

Or, 2 y = 60

∴  y = $\frac{60}{2}$ = 30  kmph

And x = 360 - 30 = 330  kmph

Hence The speed of plane in still air is 330 kmph   Answer