Multiple choice

When a natural number n is divided by 5, the remainder is 4. What will be the remainder when 2n is divided by 5?

  1. 2

  2. 3

  3. 4

  4. 0

  5. NA
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

n = 5k + 4. Then 2n = 2(5k + 4) = 10k + 8 = 10k + 5 + 3 = 5(2k + 1) + 3. The remainder when 2n is divided by 5 is 3.

AI explanation

Since the natural number n leaves a remainder of 4 when divided by 5, we can write n as 5k + 4 for some integer k. Multiplying this by 2 gives 2n = 10k + 8, which can be rewritten by taking out a multiple of 5 as 2n = 10k + 5 + 3. This simplifies to 5(2k + 1) + 3, showing that when 2n is divided by 5, the remainder is 3.

Keep practicing — related questions