Debbie’s Dragster

Debbie starts driving her dragster from rest and constantly accelerates to 60 mph in 10 seconds. How far does she travel in those 10 seconds?

1/12 mile

Ten seconds is 1/6 of a minute and 1 minute is 1/60 of an hour, so 10 seconds is 1/360 of an hour.

If you graph her trip with the speed on the y-axis and the time on the x-axis, you get a triangle with height of 60 mph and width of 1/360 of an hour. To calculate the area of the triangle, you multiply 1/2 × 1/360 × 60 = 1/12.

Posted in Brain Teasers


4 Comments on "Debbie’s Dragster"

kelechi says
May 20, 2016 @ 11:54

6 miles

froggie123 says
May 24, 2016 @ 01:50

?! I did not get that one at all!

Ellie says
October 27, 2017 @ 09:57

Too many math riddles. My brain does not like numbers!

Michael A says
November 15, 2019 @ 18:18

The answer cannot be determined. 60mph is a rate of speed. The answer infers that each second the car gains 6mph. However the riddle does not specifically state that the car gains speed at a consistent rate . It says the car “constantly accelerates”, which means that it’s gains can fluctuate over time so long as they are gaining. Therefore in order for the answer to the riddle to be correct. The riddle would need to have its verbiage changed from saying “constantly accelerating” to “consistently accelerating”. Also her car doesn’t hook & book very well so the author might want to consider getting a faster car for Debbie if your gonna call it a dragster.

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