At noon, ship A is 70 km west of ship B. Ship A is sailing south at 40 km/h and ship B is sailing north at 20 km/h. How fast is the distance between the ships changing at 4:00 PM? (Round your answer to one decimal place.)

57.6 km per hr

Step-by-step explanation:

Let us assume the horizontal distance between the ship is constant = x

= 70 Km

The ship A sails south at 40km/h is denoted as 40t

The Ship B sails north at 20 km/h is denoted as 20t

Now the vertical distance separating the two ships is

=  20t + 40t

= 60t

And, the Distance between the ship is changing

As x is constant

Now differentiating

The distance between two ships is at 4

So,  

vertical distance is

= 240

And, the horizontal distance is 70

So, the distance between the ships is  57.6 km per hr

i think 5 miles per hour

step-by-step explanation: