Question

20. Which of the following digits is ruled out in the units place of 12" + 1 for every positive integer n [NTSE/Stage-11/2017) (A) 1 (B) 3 (C) 5 (D) 7​

Answer 1

Answer:

A

Step-by-step explanation:

Answer 2

Answer:

A 1

Step-by-step explanation:

A

1

B

2

12

n

+1

2 has cyclicity =4

so checking n=1, 12

1

+1≡2

1

+1≡3

n=2, 12

2

+1≡2

2

+1≡5

n=3, 12

3

+1≡2

3

+1≡9

n=4, 12

4

+1≡2

4

+1≡7

so (1) is not coming.

and 2 also