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2012 AMC 12B Question 13

AMC12 · 2012 AMC 12B

Question 13

Two parabolas have equations $y = x^2 + ax + b$ and $y = x^2 + cx + d,$ where $a,$ $b,$ $c,$ and $d$ are integers (not necessarily different), each chosen independently by rolling a fair six-sided die. What is the probability that the parabolas have at least one point in common?
  1. $\dfrac{1}{2}$
  2. $\dfrac{25}{36}$
  3. $\dfrac{5}{6}$
  4. $\dfrac{31}{36}$
  5. $1$