Data Sufficiency

If P, Q, R are integers greater 1, have P and R common factors other than 1?
1) P and Q have common factors other than 1
2) Q and R have common factors other than 1

Since the original condition has 3 variables, we need 3 equations in order to match the number of equations and the number of variables. Thus, the correct answer is E.

- Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.