Answer to July 2008 Problem
The Bike Problem

My son-in-law bought a new mountain bike that was on sale for 20% off.
However, if he went to the store at 6:00 AM on July 4, he would receive an additional 20% off the sale price.

What was the actual percentage that his bike was discounted?

 

Solution to the Problem:

The actual discount is 36%.


Let x = original price.
After the first 20% discount, the cost of the bike is x - .20x = .8x.
After the second 20% discount, the cost is .8x - .20(.8x) = .64x.
So, the discount is 100 - 64 = 36 percent.

Correctly solved by:

1. John Funk Ventura, California
2. K. Sengupta Calcutta, INDIA
3. James Alarie Flint, Michigan
4. David & Judy Dixon Bennettsville, South Carolina
5. Tom Robb Winchester, Virginia
6. Les Walker Ventura, California