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20, What is the last digit of 33h+ 1, where n is natural number?(b) 7none of these(c) 8(a) 2 |
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Answer» (3³)⁴ⁿ = (27)⁴ⁿ = (27⁴)ⁿ = (531441)ⁿ since the last digit here 1 , so every time on putting any power on 1 , we will get 1 as the last digit. and since the question is ((3)³)⁴ⁿ +1 so, we have to add +1 to the last digit so, the last digit will become 1+1 = 2. option a no ans is (d) but how I don't know no answer should be 2 only.. check your answer. alternate method.. assume n = any natural no. say 1 now ((3)³)⁴*¹)+1 = (27)⁴*¹ = (531441)¹+1 = 531441+1 = 531442 ... laat Digit is 2 only....( my method is correct) you can check by putting different values of n , such as n=2,3 also.. you will get this result always.. remark : In exams if there comes question like these , always suppose some values on your one.. and calculate in your assumption , like i did taking n=1, you will get your answers easily. |
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