A) 1
B) 2
C) 3
D) None of these
Correct Answer: C
Solution :
Here \[\frac{^{n}{{C}_{r-1}}}{^{n}{{C}_{r}}}\] = \[\frac{36}{84}\] and \[\frac{^{n}{{C}_{r}}}{^{n}{{C}_{r+1}}}=\frac{84}{126}\]. Þ \[3n-10r=-3\] and \[4n-10r=6\] On solving, we get \[n=9\],\[r=3\].You need to login to perform this action.
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