Question

A plane takes 2 hrs and 45 mins to cover the distance between two airports. If it travels 20km/hr slower then it takes 3hrs. Find the speed of the plane. Also, find distance between the two airports.

Answer 1

it should take approximately 75

Answer 2

D=rt 
Distance is same 
let x be the speed 
D=2 3/4 *x
==11/4 x 
speed x-20 
d= (x-20)*3 
equate both 

11/4 x = (x-20)*3 
11x= 12(x-20) 
11x=12x-240 
12x=11x=240
x= 240 
speed = 240 kph 
d=rt
d= 11/4 * 240 
d=11*60
=660 km