Question

The digit in the unit place of the number $ 2009 !+3^{7886}$ is

• A. 9
• B. 7
• C. 3
• D. 1

Answer 1

Answer: (A)

The digit in the unit place of $(2009) !$ is $0 .$
Now, $3^{1}=3,3^{2}=9, \quad 3^{3}=27, \quad 3^{4}=81$,
$3^{5}=243$
$\therefore 3^{7886}=\left(3^{4}\right)^{1971} 3^{2}$
The digit in the unit place of $3^{7886}$ is $9$ .
$\therefore $ The digit in the unit place of $(2009) !+3^{7886}$ is $9 .$