Multiple choice

The LCM of 5, 8, 12 and 20 will not be a multiple of

  1. 5

  2. 3

  3. 9

  4. 20

  5. 8
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

5 = 58 = 2 x 312 = 2 x 2 x 320 = 2 x 2 x 5 LCM = 2 x 3 x 3 x 5 (Take highest power of common factor 2, 5 and remaining left out factor 3) = 120 By definition of LCM, 5, 8, 12 and 20 have to be multiples of 120, so the left out number 9 will not be a multiple of LCM.

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