I can do multivariable calc, but not an easy physics problem

MrCodeDude

Lifer
Jun 23, 2001
13,674
1
76
Link to Problem

This additional information was given: The debt, as of July 2004, of 7.26 trillion (7.26*1012) dollars.

Y = 1 / .05 * ln(x)

Y = 20 * ln(x)

But I'm confused what I'm solving for. Am I doubling the debt and sticking that in for x?
 

Soccer55

Golden Member
Jul 9, 2000
1,660
4
81
Put 2 in for x and the interest rate (in decimal form) for r. The answer you get out will be the number of years it will take for the debt to double.

-Tom
 

computeerrgghh

Golden Member
Apr 10, 2005
1,121
0
0
This is physics? :confused: The problem is asking the length of time necessary to double the debt. The actual debt is unimportant because doubling is based solely on the rate. the answer would be ln(2)/.05 or you could use the old rule of 72, which is a rough way of estimating the doubling. 72/5 = roughly 14.4 years
edit: darn too late