Answer
$t \approx 0.045$
Work Step by Step
$\ln (3t) + 5 =3$
$\ln 3t = 3 -5$
$\ln 3t = -2$
$\log_e 3t = -2$
$e^{-2} = 3t$
$t = \frac{e^{-2}}{3}$
$t \approx 0.045$
Check:
$\ln (3(\frac{e^{-2}}{3})) + 5 \overset{?}{=}3$
$\ln (e^{-2}) + 5 \overset{?}{=}3$
$\ln(e^{-2}) + 5 \overset{?}{=}3$
$(-2)\log_e(e) + 5 \overset{?}{=}3$
$-2 + 5 \overset{?}{=}3$
$3 = 3$