spectrum of beta decay is continuous;
with a maximum value of energy;
the resulting energy difference between energy of any β(+) and maximum β(+) energy is accounted for by the energy of the neutrino / reference to energy difference between parent energy level and excited energy level of daughter;

${{\text{T}}_{\frac{1}{2}}} = \frac{{{\text{In}}2}}{{0.061}} = 11.4\left( {\text{s}} \right)$;
$\left( {N = \frac{1}{8}{N_0}{\text{ so}}} \right)t = \left( {3{T_{\frac{1}{2}}} = } \right)34\left( {\text{s}} \right)$

or

$t =  - \frac{{{\text{In}}0.125}}{{0.061}}$;
t=34(s);