You didnt include the (presumably) multiple choice answers. My guess is that the answer would be along the lines of: 20 - (P times .40)
The shortest distance they have to travel to return to their starting point is 9.4 miles.
Explanation
The joggers run 8 mile north and then runs 5 miles west. we have to calculate the shortest distance they have to travel to return to their starting point.
The distance traveled north and west respectively makes the height and base of a right angled triangle.
to find the shortest distance to the starting point, the hypotenuse has to be determined.
height h=8 miles
base b=5 miles
using pythagoras theorem

The shortest distance to the starting point is 9.4 miles
The key is to do it on ur own