⇒ Total distance to be covered = total length of both the trains =152.5+157.5 =310m Total time taken =9.3sec Speed = distance ∕ time =(310∕9.3)m∕sec =(310∕9.3)×(18∕5) =120km∕hr ∴ The combined speed of the two trains every hour would then be 120km∕hr.