October 2016
Problem of the Month

Against the Wind
by Sam Loyd



A cyclist rode a mile on her bicycle in three minutes with the wind, and returned in four minutes against the wind.

Assuming that at all times she applies the same force to the pedals, how long would it take her to ride a mile if there were no wind?

Show your work!




Solution to the Problem:

It would take the cyclist 3 3/7 minutes (24/7 minutes) to ride a mile with no wind.

Let x = the speed of the cyclist with no wind.
Let y = the speed of the wind.
Then x + y = 1/3 mile/min
and x - y = 1/4 mile/min

Solving for x, add the two equations to obtain:
2x = 1/3 + 1/4
So, 2x = 7/12 or
x = 7/24 miles per min.

That means that she can ride 7 miles in 24 minutes or 1 mile in 24/7 minutes.



Correctly solved by:

1. Kimberly Howe Vienna, Virginia
2. James Alarie Flint, Michigan
3. Olivia Edwards Park Ridge, Illinois
4. Keegan Genzer Mountain View High School,
Mountain View, Wyoming
5. Tom Laidlaw Vancouver, Washington


Send any comments or questions to: David Pleacher