If in the binomial expansion of (1+x)^{n},the co-efficients of the 4th and 13th terms are equal to each other, the value of n is

 

  • Option 1)

    9

  • Option 2)

    12

  • Option 3)

    15

  • Option 4)

    17

 

Answers (1)

As we learnt in 

The 4th term

 T_{4}=^{n}C_{3}x^{3}\, \, \, \, \, \, \, \, \, \, T_{13}=^{n}C_{12}x^{3} \, \, \, \, \, \, \, \\\\Here \, \, \, ^{n}C_{3}=^{n}C_{12}

Thus n=15


Option 1)

9

Incorrect

Option 2)

12

Incorrect

Option 3)

15

Correct

Option 4)

17

Incorrect

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