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1952 AMC 12 Question 45

AMC12 · 1952 AMC 12

Question 45

If $a$ and $b$ are two unequal positive numbers, then:
  1. $\dfrac{2ab}{a+b}\gt\sqrt{ab}\gt\dfrac{a+b}{2}$
  2. $\sqrt{ab}\gt\dfrac{2ab}{a+b}\gt\dfrac{a+b}{2}$
  3. $\dfrac{2ab}{a+b}\gt\dfrac{a+b}{2}\gt\sqrt{ab}$
  4. $\dfrac{a+b}{2}\gt\dfrac{2ab}{a+b}\gt\sqrt{ab}$
  5. $\dfrac{a+b}{2}\gt\sqrt{ab}\gt\dfrac{2ab}{a+b}$