Math in the News: 8/8/11
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Transcript of Math in the News: 8/8/11
8/8/11
Federal $pending
This table shows the total government expenditures from 2000 to 2010. During this ten-year period, expenses doubled in size.
Source: http://www.whitehouse.gov/omb/budget/Historicals
Federal $pending
Here is a graph of the data from the table.
Federal $pendingThe change
from 2000 to 2010 represents a 93% increase.
Federal $pendingHow can we
use this result to determine the average year-to-year increase?
Federal $pendingUse this
formula, which shows an annual increase in spending of a constant Rate.
Federal $pending
We need to solve for the Rate.
Federal $pendingThe result is
that each year, on average, the federal budget grew by a little over 6%.
Federal $pending
• Are you surprised by the result?• Were you expecting that the annual percent increase in the budget would
be much larger than 6.8%
Federal $pendingThis is an
example of the power of compound growth.
Federal $pendingA simple way of
estimating how long it takes to double an amount of money, assuming simple interest compounded annually, is to use the Rule of 72.
Federal $pendingA graph of the
Rule of 72 results in a rational function. The y- coordinate is the number of years it takes, given the compounding rate in the x- coordinate.
US. Govt. spending: Doubles every dozen years.
Federal $pending
Next Steps
• Write a letter to your Senator or Congressman about the topic of federal spending. List some of your recommendations for controlling the growth of federal spending over the next ten years.
• BASE ALL OF YOUR RECOMMENDATIONS ON DATA THAT YOU HAVE OBTAINED AND ANALYZED.