by rfernandez Fri Jul 18, 2008 3:50 pm
The product of integers 1 to n can be expressed as a factorial: n!
There might be a formula for this, but my guess is that it's probably very cumbersome and not practical for the GMAT.
When factorials come up on the GMAT, it's usually possible to cancel common factors to make the arithmetic easier. In cases when you get large factorials and you cannot cancel them, the problem can probably be solved by some means other than evaluating the number.
Not sure what you mean by your second question.