The old miles an hour question, plz help me out!?

Question

trains a and b are traveling in the same direction on parallel tracks. train A is traveling 100 mph and train B is traveling 110 mph. Train A passes the train station at 6:20 AM and train B passes the station at 6:32am. When will train B catch up to train A? I know it is going to be AM, unless I am wrong. I have done this 3 times and keep getting a different answer. Can someone please help me out?

Answer 1

well their speed difference is

110 mph - 100 mph = 10 mph

and their arivaltime difference is

6:32 am - 6:20 am = 12 min  = 1/5h or 0.2h

in this time will the first train, travel about s=v*t = 100mph * 0.2h = 20 miles

the question is now

how long do you need to travel 20 miles with just a  speed of 10mph ( difference)

again

s=v*t

t=2h

so it takes another 2hours

answer = 8:32 am

Answer 2

i think it is 8:32 am

at 6:32 train A is 20 mile further than train B ( 12 min is 1/5 of an hour which is 20 miles when speed is 100 mph)

so at 6:32 train B needs to make up twenty mile which it is traveling 10 mph faster.

so i think in 2 hours it will catch up

Answer 3

12 minutes = (1/5) hour

train A travels 100(1/5) = 20 miles in 1/5 of an hour

So train A is 20 miles from the station when train B arrives

D1 = distance train 1 travles = 20 + 100t

D2 = distance train 2 travels = 110t

These must be equal

D1 = D2

20 + 100t = 110t

10t = 20

t = 2hours

Train B will catch up to train A in 2 hours so this will be at 8:32 AM