Chapter 9 - Section 9.5 - Exponential and Logarithmic Equations - Exercise Set - Page 728: 106

$r=0.15=15.0\%$

$P=5000, n=360, A=9000, t=4$ $A=P(1+\frac{r}{n})^{nt}=5000(1+\frac{r}{360})^{1440}=9000$ $(1+\frac{r}{360})^{1440}=1.8$ $1440\log (1+\frac{r}{360})=\log 1.8$ $1+\frac{r}{360}=1.000408$ $\frac{r}{360}=0.000408$ $r=0.14675$ rounding to one decimal $r=0.15=15.0\%$