he speed of a freight train is 30 mph slower than the speed of a passenger train. The freight travels 140 mi in the same time that it takes the passenger train to travel 210 mi. Find the speed of each train.
Let speed of freight train be S
Then speed of passenger train = S + 30.
Freight and passenger trains' times: , respectively
As their times are the same, we get the following DISTANCE equation:
------- Factoring out GCF, 70, in numerator
3S = 2(S + 30) ------ Cross-multiplying
3S = 2S + 60
3S - 2S = 60
Speed of freight train, or
You should now be able to find the passenger train's speed.