[tex]\textbf{Answer:}[/tex]
[tex]r\approx 0.13345[/tex]
[tex]\textbf{Step-by-step explanation:}[/tex]
[tex]\text{Your formula is missing something: t}[/tex]
[tex]\text{It should read }A=P(1+r)^t[/tex] [tex]\text{Where A is the final amount, P is the principal, r is rate in decimal, and t is time in years}[/tex]
[tex]\text{Given that A=3000000, P=20000, and t=40, we can subsitute and solve}[/tex]
[tex]A=P(1+r)^t[/tex]
[tex]\text{subsitute}[/tex]
[tex]3000000=20000(1+r)^{40}[/tex][tex]\text{ now solve for r}[/tex]
[tex]\text{Divide both sides by 20000}[/tex]
[tex]150=(1+r)^{40}[/tex]
[tex]\text{Take the 40th root of both sides }(\sqrt[40]{})[/tex]
[tex]\sqrt[40]{150}=1+r[/tex]
[tex]\text{subtract 1 from both sides}[/tex]
[tex]\sqrt[40]{150}-1=r[/tex] [tex]\text{ or in approximate form, }[/tex][/tex]r\approx 0.13345[/tex]
