A plane flew at 20/27 of its usual rate in a 3,000 km course due to inclement weather; thereby taking an additional 1-1/2 hours t its usual time required for the trip. What is the trip f the plane?

Solution:

The rate is x

So

3000/x - 3000/(20/27x) = -1.5

So

x = 700

So the usual rate is 700 km/h