December 2010
Problem of the Month

Pedometer Problem

Mrs. P has a pedometer that she uses when she and Mr. P go for a walk.

One day, Mrs. P wore pants that did not have a pocket, so, she gave Mr. P her pedometer.

The problem with that is that the pedometer is set for Mrs. P's stride, so it measured the number of steps that Mr. P took but it calculated the distance they walked at Mrs. P's stride.

At the end of their walk, the pedometer registered 830 steps and 3.75 miles.

If Mr. P takes 89 steps for every 100 steps that Mrs. P takes, how far did they walk?

Give your answer in miles to two decimal places.

Solution to the Problem:

The answer is 4.21 miles.

First, determine the number of steps that Mrs. P took by solving the proportion:
89 / 100 = 830 / x, where x is the number of steps that Mrs. P took.
So, Mrs. P took 932.584 steps.

Next, determine the length of Mrs. P's stride by dividing 3.75 miles by 830 steps.
So, her stride is .00451 miles.

Then multiply these two numbers together to find the distance that the Ps walked:
Distance = 932.584 x .00451 = 4.21 miles.

Correctly solved by:

1. Brandon Preston	Mountain View High School, Mountain View, Wyoming
2. Jacob Harmon	Mountain View High School, Mountain View, Wyoming
3. Victoria Johnson	Mountain View High School, Mountain View, Wyoming
4. David & Judy Dixon	Bennettsville, South Carolina
5. John Funk	Ventura, California

Send any comments or questions to: David Pleacher