Subject: General Aptitude · Chapter: Number System · Exam: 2010 · Marks: · Difficulty:
The unit's digit of $13^{2003}$ is
(a)1
(b)3
(c)7
(d)9
Answer
Answer (as printed): C
Explanation
$3^{4}$ gives unit digit 1. So, $\left(3^{4}\right)^{500}$ gives unit digit 1. And, $3^{3}$ gives unit digit 7. $\therefore \quad(13)^{2003}$ gives unit digit $=(1 \times 7)=7$.
Explanation as extracted from the printed page; notation may be imperfect.