Question

Two trains start at stations that are 140 km apart. If Train A heads south at 24 km/hr and Train B heads north at 7 km/hr, how long will it be before they pass each other? Report your answer to 1 decimal place. Do not type in the unit or the computer will mark your answer incorrect.

Answer 1

V = V1 + V2 since V1 and V2 are in opposite directions their rate of approach will be the sum of their individual speeds

V = 24 km/hr + 7 km/hr = 31 km/hr

T = 140 km / 31 km/hr = 4.52 km/hr or 4.5 without units