Originally Posted by
Opalg As stated here, there is no plausible solution. In fact, 1894 = 2×947, both of which factors are prime. So either there were 2 students and the cafeteria was ripping them off, or there were 947 students and the cafeteria is heavily subsidised.
In fact, I believe that the total payment should be $18.49. In that case, 1849 = 43^2. That gives a unique solution: 43 students, each paying 43¢. That's pretty good value for tea and a sandwich. I guess the cafeteria is subsidised after all.