The user-friendly version of this content is available here.
The following content is copyright (c) 2009-2013 by Goods of the Mind, LLC.
This problem trains for: SAT-I, AMC-8, GMAT.
How many primes p are there such that:
is a perfect square?
Since the expression:
is odd, the perfect square in question must also be odd:
After algebraic manipulation:
and the possibilities for obtaining a product of two consecutive positive integers are:
Therefore, there are three possible primes that satisfy the equation.