Answer
0.57 g
Work Step by Step
$t=5.5\,d$
$N_{0}=1.55\,g$
$t_{1/2}=3.8\,d$
$k=\frac{0.693}{t_{1/2}}=\frac{0.693}{3.8\,d}=0.1823684\,d^{-1}$
Recall: $\ln \frac{N_{t}}{N_{0}}=-kt$
$\implies \ln \frac{N_{t}}{1.55\,g}=-0.1823684\,d^{-1}\times5.5\,d=-1.003$
$\implies \frac{N_{t}}{1.55\, g}=e^{-1.003}= 0.366777 $
$\implies N_{t}=1.55\,g\times0.366777= 0.57\,g$
