Answer:
1
Step-by-step explanation:
First, draw a diagram to visualize the situation:
As we can see, the difference between the x-coordinates of the points is the length of one leg of a right triangle, and the difference between the y-coordinates is the length of the other leg.
Then, for the given points (-5,4) and (8,-3), the distance given by the Pythagorean Theorem is:

Therefore, the distance between the points (-5,4) and (8,-3) is: √218.
It will take him 16 hours because 25 is 1/4 of 100% so 4 times 4 is 16. So 16 is your answer :)