# Easy Number System Solved QuestionAptitude Discussion

 Q. What is the remainder when $7^{187}$ is divided by $800$?
 ✖ A. 143 ✖ B. 243 ✔ C. 343 ✖ D. 443

Solution:
Option(C) is correct

$7^{187} = (7^4)^{46} × 7^3 = (2401)^{46}×343$

Now $2401 = 2400+1$, where $2400$ is perfectly divisible by $800$

$\Rightarrow (2401)^{46}$ is divided by $800$, the remainder must be $1$

So, the remainder when $7^{187}$ is divided by $800$ is $1×343 =\textbf{343}$