# 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

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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