If n is a positive integer and k + 2 = 3^n, which of the following could NOT be a value of k ?
(A) 1
(B) 4
(C) 7
(D) 25
(E) 79
possible values
3=3 unit digit=3
3*3=9unit digit=9
3*3*3=27unit digit=7
3*3*3*3=81unit digit=1
this will repeat again.. forever
so,
3-2=1
9-2=7
7-2=5
1-2=9 or -1
so we will never get 4, thus B is the answer to the question.
(A) 1
(B) 4
(C) 7
(D) 25
(E) 79
possible values
3=3 unit digit=3
3*3=9unit digit=9
3*3*3=27unit digit=7
3*3*3*3=81unit digit=1
this will repeat again.. forever
so,
3-2=1
9-2=7
7-2=5
1-2=9 or -1
so we will never get 4, thus B is the answer to the question.
