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Question of the Day

Below is my favorite question of all time. It has been years since it was recounted to me so I can’t attribute it; however I always end up pulling it out in conversations to have a bit of fun with guests, especially those with math, engineering or physics backgrounds.


You have a one mile race track in the shape of a loop. A man is wants to race around the track twice with an average speed of 60 miles per hour. The racer completes the first lap going 30 m.p.h.


How fast does the racer have to go on the second lap to make his average speed 60 m.p.h over the 2 lap race?

Hint: If the answer were 90 m.p.h, this wouldn’t be a very good question would it?



3 thoughts on “Question of the Day

  1. Is the answer 120 miles per hour

    Posted by Mike | August 3, 2008, 3:44 pm
  2. No, sorry. It can be tricky, but I feel confident if you were to bust out the Speed, Distance, Time formula from long ago you should come up with the answer pretty quickly.

    Posted by matthewbingram | August 3, 2008, 4:54 pm
  3. Okay, Matty, you trickster, you. You ask the impossible!

    This looks to be a simple D=R*T solution, and by calculating each lap individually, you should come up with the answer. That is, until you try to calculate each lap individually and find the math doesn’t work. Tricky, tricky!

    So, let’s follow my pencil and see how it unfolds…

    D=R*T orrrrrrr R=D/T
    In order to complete the race with a two lap average of 60MPH, the rate would have to be 2/60th or 1/30th. But when you calculate lap one; you get the full 1/30th. And since it’s physically impossible for a racer to complete a lap in “no” time, his rate of speed in the first lap makes it impossible for the racer to complete both laps with the target rate of 1/30th.

    He can’t do it. Even if he goes the speed of light.


    Posted by Suze | August 5, 2008, 2:39 pm

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I hope you enjoy my personal blog. I'll publish posts on various topics and voice my opinions on an eclectic array of things.

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Blog Created On: July 28, 2008 E-mail: crossover65@hotmail.com

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