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

Seventeen hours and fifteen minutes

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