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1962 AMC 12 Question 32

AMC12 · 1962 AMC 12

Question 32

If $x_{k+1}=x_k+\dfrac12$ for $k=1,$ $2,$ $\ldots,$ $n-1$ and $x_1=1,$ find $x_1+x_2+\cdots+x_n.$
  1. $\dfrac{n+1}{2}$
  2. $\dfrac{n+3}{2}$
  3. $\dfrac{n^2-1}{2}$
  4. $\dfrac{n^2+n}{4}$
  5. $\dfrac{n^2+3n}{4}$