## Thinking Mathematically (6th Edition)

$6\% = r$
RECALL: The formula for the future value $A$ is: $A=P(1+rt)$ where P= principal amount borrowed r = interest rate per year t = time in years Use the formula above, with $A=\$3180$,$P=\$3000$, and $t=1$, to obtain: $\$3180 = \$3000(1+r \cdot 1) \\\$3180 = \$3000(1+r)$ Divide $\$3000$on both sides of the equation to obtain:$\frac{3180}{3000} = 1+r \\1.06 = 1+r$Subtract$1$on both sides of the equation to obtain:$0.06 = r$Convert to percent to obtain:$6\% = r\$