Question

Benjamin and Bob are marathon runners on a run from landmarks P to Q. Benjamin runs half the way and walks the other half. Bob runs half the time, and walks the other half. The two run at the same speed and walk at the same speed. Who finishes first?

Answer 1

Ben takes time t = (d/2)/r + (d/2)/w = d/(2(r+w))
Bob covers distance w(t/2) + r(t/2) = d
so Bob's time is 2d/(r+w)

So, which time is less?