[tex]63000=47000(1+0.045)^t[/tex] divide both sides by 47000 [tex] \frac{63}{47} =(1.045)^t[/tex] take the ln of both sides [tex] ln(\frac{63}{47}) =ln((1.045)^t)[/tex] [tex] ln(\frac{63}{47}) =t(ln(1.045)[/tex] divide both sides by ln(1.045) [tex] \frac{ln(\frac{63}{47})}{ln(1.045)}=t [/tex] using calculator 6.656=t so after about 6.7 years
