Math challenge

Here's a math challenge for you: Suppose you are traveling at 70 mph, while a mile-long train headed in the same direction and parallel to the freeway is traveling at 50 mph. How long will it take to pass the train?


Hint: Convert miles per hour to feet per minute, then try a few scenarios such as where would the car and the front of the train be after one minute, after two minutes, after three minutes, after five minutes, et cetera.
Solution: To convert mph to feet per minute, multiply by 5,280 feet/mile and divide by 60 min/hour; thus traveling at 70 mph is equal to 6,160 feet/min, while 50 mph = 4,400 feet/min. Check your answer so far. (Note: Traveling at 60 mph is equal to going one mile per minute; does it make sense that going 70 mph means you can cover more than one mile in one minute, while traveling at 50 mph means you would travel less than one mile in one minute?) Next, determine where the front of the train and the car would each be after one minute, two minutes, et cetera. Train 5,280 + 4,400 + 4,400 + 4,400 + 4,400 + 4,400 Total 9,680 14,080 18,480 22,880 27,280 feet 1 min 2 min 3 min 4 min 5 min Car 6,160 + 6,160 + 6,160 + 6,160 + 6,160 Total 6,160 12,320 18,480 24,640 30,800 feet So, it becomes apparent that the car will pass the train after 3 minutes.


Jon A.

Math, English Tutor

900+ hours
if (isMyPost) { }