At noon, ship A is 110 km west of ship B. Ship A is sailing east at 20 km/h and ship B is sailing north at 15 km/h. How fast is the distance between the ships changing at 4:00 PM

Explanation:

= Rate at which the distance between A and starting point of B is changing = -20 km/h

= Rate at which the distance of B is changing = 15 km/h

= Rate at which the distance between A and B is changing

Time after which the rate at which the distance between A and B is changing is 4 hours

Distance covered by A in 4 hours =

a = Distance remaining to the start point of B =

b = Distance covered by B in 4 hours =

Distance between A and B after 4 hours

Differentiating with respect to time we get

The rate at which the distance between the ships is changing at 4 PM is .