The train starts at station 1. The train stays at each station for 45 seconds. The question asks how long it will take to get from the first station to the last station. The train stays at each station for 45 seconds, but when the train gets to the last station, the problem ends; therefore we don't have to consider the 45 seconds it stays at station 12. Again, the problem ends when the train gets to station 12 !
We have to consider 45 seconds at each station for only 11 stations; therefore we have (11*45)/3600. We divide by 3600 seconds in an hour.
distance=rate*time and time=distance/rate
To go from station 1 to station 12, the train moves only 11 times.
0.55*60(minutes)=33 minutes to get from station 1 to station 12
Remember, the problem asks how long it takes to get from station 1 to station 12. When the train gets to station 12, the problem ends.