Answer:
The answer to the question is
it will take Dave 108.399 months or 9.03 years to reduce the balance to $0
Step-by-step explanation:
To solve the question, we note that
Balance cresdit = $20,000
APR = 20%
PMT = $400 per month we have
[tex]A = P(1+\frac{r}{n} )^{nt}[/tex] and
[tex]A=P\frac{r(1+r)^n}{(1+r)^n-1}[/tex] where r = 20 %÷12
P = $20000 and A = 400
Therefore we have[tex]400 = 20000\frac{\frac{0.2}{12} (1+\frac{0.2}{12})^n }{(1+\frac{0.2}{12})^n-1}[/tex]
which gives 6/5=[tex]\frac{ (\frac{61}{60})^n }{(\frac{61}{60})^n-1}[/tex]
= [tex](\frac{61}{60})^n[/tex] = 6 that is ln [tex](\frac{61}{60})^n[/tex] = ln (6) or n = [tex]\frac{ln(6)}{ln(\frac{61}{60}) }[/tex] = 108.399 months = 108.399/12 or 9.03 years