Atrain leaves a station and travels north at a speed of 45km/h. two hours later a second train leaves on a parallel track and travels north at 75km/h. how far from the station will they meet ?

Recall your d = rt, distance = rate * time.

A = first train.

B = second train leaving 2 hrs later.

if say by the time they meet, train B has traveled "t" hours, we know that train A has been traveling 2 hours more than that, because it left 2 hours earlier than train B, thus it has traveled "t + 2" hours.

keeping in mind that by the time they meet, they both have traveled "d" kilometers.