T1 + t2 = 2h and 30min;
t1 * 600 = t2 * 400 => t2 = (3/2) * t1;
then, t1 + (3/2) * t1 = 2h and 30min => 2t1 + 3t1 = 5h => 5*t1 = 5h => t1 = 1h => t2 = 1h and 30 min;
The distance is 2 * 1 * 600 = 1200miles;
We are given a line segment with two points on each end. Rebecca draws two arcs with equal radius from each point. Now, the intersection of the two arcs is the midpoint of the line. This can be explained by the radius of the arcs. Since they are equal, meaning they have the same distance from each point. Thus, the midpoint of the line.
Your answer is b. hope this helps :)