When a positive integer x is divided by 5, the remainder is 3. What is the remainder when 3x is divided by 5?

✓ Correct Answer: Option D

If x = 5k + 3 for some integer k, then 3x = 3(5k + 3) = 15k + 9. Dividing 15k by 5 gives a remainder of 0. Dividing 9 by 5 gives a remainder of 4. Thus, the remainder for 3x divided by 5 is 4.