Towns A and B are 400 miles apart. If a train leaves A in the direction of B at 50 miles per
hour, how long will it take before that train meets another train, going from B to A, at a speed
of 30 miles per hour?
(A) 4 hours
(B) 4 hours
(C) 5 hours
(D) 5 hours
(E) 6 hours