Answer
225 K or $-48^{\circ}C$
Work Step by Step
We find:
$\frac{V_{1}}{T_{1}}=\frac{V_{2}}{T_{2}}$ (at constant n and P)
$\implies T_{2}=\frac{V_{2}T_{1}}{V_{1}}=\frac{(1.50\,L)(177+273)K}{3.0\,L}$
$=225\,K=(225-273)^{\circ}C$
$=-48^{\circ}C$
