Problema Solution
The subway offers access to all 12 intersections downtown. If every intersection is .75 miles apart and the train travels at 20 mph and spends 45 seconds at every stop to unload and upload new customers, how long will it take to get from the first intersection to the last intersection?
Answer provided by our tutors
we assume the train starts at the first intersection and is able to start and stop instantaneously at each intersection, then spends exactly 45 seconds at every stop
the train begins at a stop and will then have 11 intersections to travel to and stop at but we only have to arrive at the last intersection, so we exclude the 45 second wait time from that intersection
distance = speed * time
time = distance / speed
45 seconds = 45/3600 hours
(11 * 0.75)/20 + 10*(45/3600) = 0.5375
0.5375 * 60 = 32.25
under these circumstances, it will take 0.5375 hours, or 32.25 minutes, to get from the first intersection to the last intersection