Air flows adiabatically through a duct. At the entrance, the static temperature and pressure are \(310 \mathrm{~K}\) and \(200 \mathrm{kPa}\), respectively. At the exit, the static and stagnation temperatures are \(294 \mathrm{~K}\) and \(316 \mathrm{~K}\), respectively, and the static pressure is \(125 \mathrm{kPa}\). Find

(a) the Mach numbers of the flow at the entrance and exit 

(b) the area ratio \(A_{2} / A_{1}\).