For all you math lovers...?

Question

The Forever Stamp features the Liberty Bell image and the word "forever." It will always be available at the price of a First-Class Mail stamp in effect at the time of purchase. To introduce the stamp to the public, the Postal Service began offering the stamp on April 12, 2007 at 41 cents. Customers may use the stamp as soon as they wish, but stamp prices will not change until May 14. When prices change in the future, the Forever Stamp will sell at the new one-ounce, single-piece First-Class Mail price. It has been suggested that you might want to stock up on these new 41 cent stamps to avoid price hikes in postage in the future. Let’s see if this is a good idea.



On May 14, 1975 the single-piece First-Class Mail price was 10 cents for the first ounce. On May 14, 2007 the price will increase to 41 cents for the first ounce. What is the percent increase in the one-ounce, single-piece First-Class Mail price during that time period?

Answer 1

:)
percent increase means

(final price - initial price) / initial price

(0.41 - 0.10) / 0.10 = 3.1

====> change to percent 310%

WOW!
:)

Answer 2

It was a 310% percent increase, but if you look at the yearly percent increase. .10x^32 = .41. You get 4.5% a year, which is a return below what you can get by putting your money in a decent mutual fund, or by paying off outstanding debt.

Answer 3

(41 - 10) / 10 = 3.1 = 310%