Answer:
12:00 AM
Step-by-step explanation:
Taking the lodge as the center of the coordinate system, the position of each person is:
William: 6+3*t
Nancy: 5*t
Edgar: 12*t
where t is in hours after 10:00 am
Between the positions of William and Nancy, a right triangle is formed, where their distance is the hypotenuse.
WN = √[(5*t)² + (6+3*t)²]
Similarly, Between the positions of Nancy and Edgar:
NE = √[(5*t)² + (12*t)²]
If the distance between Nancy and Edgar is 10 miles greater than the distance between Nancy and Willam, then
NE = WN + 10
√[(5*t)² + (12*t)²]  = √[(5*t)² + (6+3*t)²] + 10
With the help of the graph of this equation, we find that t = 1.95 or approximately 12:00 AM
