Question

An aircraft flying at an average speed of 770 km/h takes 15 hours to complete a journey. Find the time taken for the aircraft to complete at same journey if it's average speed is 660 km/h

Answer 1

Seventeen hours and fifteen minutes

Answer 2

We can solve it two ways, we´ll do it via physics:
We know that:
d=vt
d=770km/h*15h
d=11550km
Now at 660km/h:
t=d/v
t=11550km/660km/h
t=17,5h
Math way:
770km/h→15h
660km/h→x
So:
(770*15)/660=x
x=17,5h