NTSE Stage 2 SAT 2018 Exam Question Paper

Question : 42 of 100

Marks: +1, -0

Which of the following digits is ruled out in the units place of

12^n+1

for every positive integer n ?

Solution:

Since, the unit digit of

(12)^n

for positive integer n are 2, 4, 6, 8
Then, the unit digit of

12^n+1

will be 3, 5, 7, 9
Hence, 1 is ruled out in the unit place because

12^n+1

can not have 1 as its unit digit.

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