Two surveyors with two-way radios leave the same point at 9: 00 a.m., one walking due south at 3 mi/hr and the other due west at 4 mi/hr. how long can they communicate with one another if each radio has a maximum range of 6 miles?

Let they communicate with one another  for time t.

Please see the attached image.

We have been given that each radio has a maximum range of 6 miles. Hence, the hypotenuse of the triangle is 6.

We know the formula

Using this formula, we have

Now, using Pythagorous theorem, we have

Therefore, they can communicate for 1.20 hours.