first train leaves station going 60 mph. 30 minutes later, 2nd train leaves same station going 72 mph. what is equation that tells us how long before 2nd train catches up with 1st train? We know the answer is 2 hours but don't know equation to show this.
algebra equation from word problem
The answer is not 2 hours.
The trains will meet up when the first train has been going for 3 hours and the second train has been going for 2.5 hours. Each will have travelled 180 miles at that point in time.
t is the time that the first train has been traveling in hours.
t-0.5 is the time that the second train has been traveling in hours.
Distance that the first train travels during that time is
Distance that the second train travels is
The two trains are at the same distance when those two expressions are equal
t*60 = (t-0.5)*72
60t = 72t-36
36 = 12t
3 = t
I hope that helps.