Multiple choice

If k is a positive integer, which of the following must be an even integer?

  1. k2

  2. k(k - 1)

  3. k - 1

  4. 3k + 1

  5. 4k + 3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Since we have to test all the choices, Let us consider one odd value (1) for k. Then (1) = 1, (2) = 0 , (3) = 0, (4) = 4 and (5) = 7. Now let us consider one even value (2) for k. Then (1) = 4, (2) = 2, (3) = 1, (4) = 7 and (5) = 11.In both cases Choice (2) is even, is the answer.

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