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1989 AMC 12 Question 20

AMC12 · 1989 AMC 12

Question 20

Let $x$ be a real number selected uniformly at random between $100$ and $200.$ If $\lfloor\sqrt{x}\rfloor=12,$ find the probability that $\lfloor\sqrt{100x}\rfloor=120.$ ($\lfloor v\rfloor$ means the greatest integer less than or equal to $v.$)
  1. $\frac2{25}$
  2. $\frac{241}{2500}$
  3. $\frac1{10}$
  4. $\frac{96}{625}$
  5. $1$