A cargo train and a passenger train, which start from two stations that are 710 km apart, are traveling towards each other. The cargo train started an hour before the passenger train, and is traveling with a speed of 110 km/hour. In how many hours will the cargo train and the passenger train meet, if the passenger train is traveling at 90 km/hour?

5 answers

Since the cargo train started an hour ago it already covered 110km of distance, meaning, the distance between the two trains is exactly 600km when the passenger train takes off. One hour later, the passenger train travels 90km and the cargo train another 110km so now they are only 400km away, the pattern here is that the trains are getting 200km closer to eachother in one hour. Another hour passes and the two trains are only 200km apart, then, exactly one hour later they meet. That's a total of 3 hours.

TL;DR: They will meet in 3 hours.
Actually 4 hours if you count the first hour where the passenger train isn't moving.
Thank you!
Vc * T + Vp * (T-1) = 710.
110*T + 90*(T-1) = 710,
110T + 90T - 90 = 710,
200T = 800,
T = 4 h.
bal