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IMAS 2022–2023 Junior Division — First Round Question 16

IMAS · IMAS 2022–2023 Junior Division — First Round

Question 16

In the Fibonacci sequence $\{F_k\}$, $F_1=F_2=1$ and $F_{k+1}=F_k+F_{k-1}$ for $k\ge2$. What is the value of $\frac1{F_1F_3}+\frac1{F_2F_4}+\frac1{F_3F_5}+\frac1{F_4F_6}+\frac1{F_5F_7}+\frac1{F_6F_8}+\frac1{F_7F_9}+\frac1{F_8F_{10}}$?
  1. 1
  2. $\frac{1869}{1870}$
  3. $\frac{1154}{1155}$
  4. $\frac{713}{714}$
  5. $\frac{4894}{4895}$