I'm attempting to help a tutoring student with this problem and I'm having trouble figuring out how to do it. 1. The problem statement, all variables and given/known data A marathon runner likes to practice by running in a large park that has a perfectly circular trail, with circumference 50 kilometers. She runs at a constant training speed, and to complete the entire circle takes her 2 hours and 55 minutes. However, it’s her habit that the moment she feels too tired, she stops running on the trail and starts walking on a straight line across the meadow, directly back to her starting point, at a speed exactly 50% of her running speed. Depending on where she might tire out on the circle, what is the maximum amount of time that she might spend on the run/walk, to the nearest minute? Let (x,y) =(0,0) be the center of the circular track. Let the runner's starting/ending point be the rightmost point on the circle; that is, (r,0) (in both coordinate systems). 2. Relevant equations C=2πr, C= circumference, r= radius d=s*t, d= distance, s=speed, t=time a=θ*r, a=arc length, θ=angle, r=radius d=√[(x2-x1)+(y2-y1)], d=distance between two points x=rcosθ, x=rectangular coordinates, (r,θ)=polar coordinates y=rsinθ, y=rectangular coordinates, (r,θ)=polar coordinates 3. The attempt at a solution I have no idea how to help him. Can anyone see where to go with this problem? It's been such a long time since I have calc 1 and I am completely lost here.