If = 2 : 1, find the value of n.

Given Equation :



To Find : Value of n


Formula :


By given equation,





By using above formula,



Cancelling terms (n - 4)! And (2!),



(n - 2) × (n - 3) = 6


(n - 2) × (n - 3) = (3) × (2)


By comparing both the sides,



Conclusion : Value of n is 5.


Note : Instead of taking product of two brackets in eq(1), it is easy to convert the constant term that is 6 into product of two consecutive numbers and then by observing two sides of equation we can get value of n.


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