Multiple choice

The mean of $1, 2, 3,\cdots \left ( n+1 \right )is\ \dfrac{6n}{11}$, then the value of n equals

  1. $20$
  2. $22$
  3. $18$
  4. $11$
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B Correct answer
AI explanation

The mean of the first n+1 natural numbers is given by the formula (n+1)(n+2) divided by 2(n+1), which simplifies to (n+2) divided by 2. Setting this equal to 6n divided by 11 gives 11(n+2) equals 12n. Solving this equation gives 11n plus 22 equals 12n, meaning n is 22.

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