I have a question on Gas Dynamics, we were going over a problem in class in which the problem asks to solve for the Mach number at the throat of a converging-diverging nozzle. I assumed that the Mach at the throat should be equal to 1 since the professor said it was impossible to have a Mach number greater then 1 at the throat. After showing the same problem to a Graduate Student I work with he showed me that it is possible to have a Mach number greater then 1 at the throat through the area ratios. But after speaking to my professor a second time he has again said it is not possible. So my question is.. is it possible to have a Mach number greater than 1 at the throat? Oh the conditions for the problem are as follows: Mi=2 Ai=20 cm^2 Athroat=15cm^2 Shock Area=22 cm^2 Ae=25cm^2 where gamma= 1.4 according to the solutions Mach at the throat equals 1.662 If anyone could clear up my confusion I'd appreciate it thanks!