Answer
$7.5\times10^{-23}s$.
Work Step by Step
The Heisenberg uncertainty principle states $\Delta E \Delta t \approx \frac{\hbar}{2}$. Here, $\Delta E$ is the energy width, and $\Delta t$ is the lifetime.
$\Delta t \approx \frac{\hbar}{2 \Delta E}=7.5\times10^{-23}s$.
