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JEE Mains · Maths · STD 11 - 13. statistics

\(3,7,12, a, 43-a\) નું વિચરણ, એક પ્રાકૃતિક સંખ્યા થાય તેવા \(a \in N\) ના મૂલ્યોની સંખ્યા \(\dots\dots\dots\) છે.  (મધ્યક \(=13\))

  1. A \(0\)
  2. B \(2\)
  3. C \(5\)
  4. D અનંત
Verified Solution

Answer & Solution

Correct Answer

(A) \(0\)

Step-by-step Solution

Detailed explanation

Mean \(=13\) Variance \(=\frac{9+49+144+ a ^{2}+(43- a )^{2}}{5}-13^{2} \in N\) \(\Rightarrow \frac{2 a^{2}-a+1}{5} \in N\) \(\Rightarrow 2 a^{2}-a+1-5 n=0\) must have solution as natural numbers its \(D=40 n-7\) always has \(3\) at unit place \(\Rightarrow D\) can't be perfect…
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