Q84 / 180 · KCET 2011 · Mathematics
The digit in the unit's place of $7^{171}+(177) !$ is
- A3
- B2
- Correct answerC1
- D0
Solution
Given expression
$$
(7)^{171}+(177) !
$$
We know that the cycle of 7 is 4 , i.e., $(7)^{3}=1$ and in case of more the 4 number in factorial notation gives always 0 at unit place.
$$
\Rightarrow \quad\left(7^{3}\right)^{57}+(177) !=1+0=1
$$
Hence, the correct answer is option: 'C'.