Highly selective Backlog Qs for JEE MainMathematicsBinomial Theorem

Let n=1 !+4 !+7 !+ +400 ! . Then ten's digit of n is

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Correct answer

B. 6

Step-by-step solution

Given, n=1 !+4 !+7 !+ +400 !1 !=1,4 !=24,7 !=5040,10 !=3628800 and further the terms has last two digits =00 So, 1 !+4 !+7 !+ +400 != 65 Here ten digit is 6 . Hence, 6 is the answer.

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