Two trains leave a city at the same time. one train goes west at a constant rate of 60 mph. the other goes east at a rate of 50 mph. how long will it take the trains to be 550 miles apart?

Hello!

The trains are going in opposite directions, one at 60 mph and the other at 50 mph. We can use this information to create the following formula, where variable "h" represents the number of hours:

50h + 60h = 550

Combine like terms:

110h = 550

Divide both sides by 110:

h = 5

We have now proven that it would take 5 hours for the two trains to be 550 mile apart.

I hope this helps!

Lets t   be the time that needed for trains to be  550 mi apart.
1st train will go (60*t) mi
2nd train will go (50 *t) mi
Altogether
(60t +50t), at the same time this distance equals 550 mi.
So, we can write
60t +50t =550
110t = 550
t=550/110
t=5 h

Iam thinking the answer is a.) knew