# Math puzzle

• Jan 19th 2009, 09:41 AM
karimwahab
Math puzzle
After a math lecture in Harvard the students went to the cafeteria and each one of them took a cup of tea and cheese sandwich. They all paid \$18.94. How many students where they?
• Jan 19th 2009, 11:39 AM
mr fantastic
Quote:

Originally Posted by karimwahab
After a math lecture in Harvard the students went to the cafeteria and each one of them took a cup of tea and cheese sandwich. They all paid \$18.94. How many students where they?

There is insufficient information to give a unique answer.
• Jan 20th 2009, 04:00 AM
Opalg
Quote:

Originally Posted by karimwahab
After a math lecture in Harvard the students went to the cafeteria and each one of them took a cup of tea and cheese sandwich. They all paid \$18.94. How many students where they?

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.
• Jan 20th 2009, 04:36 AM
Mush
Unless this is a trick question in which the solution is to look up Harvard policies to see what their maximum class size is! Or what the seating configuration is in their Mathematics lecture halls.
• Feb 2nd 2009, 08:57 PM
Yendor
Quote:

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.

But did each student pay the same amount?
• Feb 3rd 2009, 06:37 AM
Mush
Quote:

Originally Posted by Yendor
But did each student pay the same amount?

Why wouldn't they?