What was the speed of the train A?

Question

Train A and B started traveling in the same direction at the same time on parallel tracks. Train B was traveling at a speed of 60 mph and train A was 45 miles behind the train B at the start. After 3 hours they both arrived at a station at the same time. What was the speed of the train A?

Answer 1

distance=rate*time

d=rt

d=60*3 for train B, so d=180  miles

d+45=r*3 for train A

substitute

180+45=3r

225=3r

r=225/3

r=75 mph

 

Answer 2

Train B traveled 180 miles in 3 hours.

Train A must travel 45 miles more, or 225 miles, in 3 hours

X = speed of train A

the product of speed and time is distance traveled

 

3X = 225

X = 75