Answer
As measured in the lab, the lifetime is 910 seconds.
Work Step by Step
We can find the Lorentz factor $\gamma$:
$K = (\gamma-1)~m~c^2$
$\gamma = 1+\frac{K}{m~c^2}$
$\gamma = 1+\frac{ 25~MeV}{939.57~MeV}$
$\gamma = 1.0266$
We can find the decay time $\Delta t$ in the lab frame:
$\Delta t = \gamma~\Delta t_0$
$\Delta t = (1.0266)(886~s)$
$\Delta t = 910~s$
As measured in the lab, the lifetime is 910 seconds.
