Numerical Problems: The U.S. National Debt

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Homework Help Overview

The discussion revolves around the U.S. national debt and the implications of compound interest on its growth. Participants explore how long it would take for the national debt to double at an average interest rate of 5%, using the formula for compound interest.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the formula Y=1/r ln(x) to determine the time for the debt to double. Some express confusion about the application of the formula, while others suggest it may be simpler than initially thought. Additionally, one participant introduces the Rule of 72 as an alternative method for estimating the doubling time.

Discussion Status

The discussion is active, with participants sharing different perspectives on calculating the doubling time of the debt. Some have provided numerical estimates based on their calculations, while others question the assumptions and methods used. There is no explicit consensus on the best approach, but various interpretations are being explored.

Contextual Notes

Participants mention the average interest rate of 5% and the context of the U.S. national debt, including references to significant figures like $14 trillion and $112 trillion in liabilities. There is also mention of practical challenges in calculating large sums, indicating the complexity of the topic.

sfgradv
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Like any loan, the government accrues interest that compounds over time on the amount it owes. If the annual interest rate is r, then the number of years it takes for the amount of money owed to increase by a factor of x is

Y=1/r ln(x)

where ln is the natural logarithm.

The average interest rate on the U.S. national debt is about 5%. If the government neither borrows any more money, nor pays back any of the money it owes, how many years will it take for the total debt to double?

Give your answer using the built-in function ln.
 
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sfgradv said:
Like any loan, the government accrues interest that compounds over time on the amount it owes. If the annual interest rate is r, then the number of years it takes for the amount of money owed to increase by a factor of x is

Y=1/r ln(x)

where ln is the natural logarithm.

The average interest rate on the U.S. national debt is about 5%. If the government neither borrows any more money, nor pays back any of the money it owes, how many years will it take for the total debt to double?

Give your answer using the built-in function ln.

have you even tried this? you have the r, you have x, all you have to do is evaluate.

what's the confusion?

edit: misread - it's even easier than i thought?
 
the rule of 72 : (divide interest rate by 72)
a compoundeed value doubles every 14.4 years at 5%

there, that was simple. But the real question is, what payment and for how long would be needed to actually reduce the $14 trillion debt to 0? Since my HP 12c 25th anniversary platinum calculator only goes to 999 billion I had to use an excel spreadsheet to figure that out as I did not have one of the newly issued governemnt calculators that does trillions.

It would take $1.97 BILLION A DAY FOR 2010 years to repay that amount.

Since we started counting time.

The $112 trillion unfunded liability assuming the same interest rate? $15.3 BILLION A DAY for 2010 years.

that's a grand total of $17. 27 BILLION A DAY for 2010 years to be debt free or "pay as you go" as they like to say in Congress.

Got any gold?
 
Debt management service is pretty straight forward and you will be on your way for hassle free life..There are number of things which one has to take care of -Insurance,mortgage and cut the cost of your expenses ...A person has to be vigilant about the hidden cost and charges... There are professionals from http://www.bestdebthelpprogram.com/ who actually give a sound advice to their clients so that they can have hard earned money saved for their families.
 
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