Answer
$6\% = r$
Work Step by Step
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:
$6\% = r$
