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2014 AMC 12B Question 13

AMC12 · 2014 AMC 12B

Question 13

Real numbers $a$ and $b$ are chosen with $1 \lt a \lt b$ such that no triangle with positive area has side lengths $1,$ $a,$ and $b$ or $\tfrac1b,$ $\tfrac1a,$ and $1.$ What is the smallest possible value of $b?$
  1. $\dfrac{3+\sqrt{3}}{2}$
  2. $\dfrac{5}{2}$
  3. $\dfrac{3+\sqrt{5}}{2}$
  4. $\dfrac{3+\sqrt{6}}{2}$
  5. $3$