Cracking The SAT Premium

Percent Change

There’s one more fundamental concept that you should know about percents. Some problems will ask for
a percent increase or decrease. For these problems, use the following formula.

%   change  =       ×   100

Most of the time that you use the formula, it will be pretty clear which number you should use for the
original. However, if you’re not sure, remember that you should use the smaller number for the original if
you are finding a percent increase. You should use the larger number for the original if you are finding a
percent decrease.

Here’s an example of how to use the formula:

8.

The chart   shown   above   shows   the number  of  visits, in  thousands,  at  Arches  National

Park    for the years   2003    to  2006.   Which   of  the following   is  the closest approximation   of

the percent increase    in  the number  of  visits  from    2004    to  2006?

A) 5%