If n and m are both multiples of k, which of the following may NOT be

Question

If n and m are both multiples of k, which of the following may NOT be a multiple of k?
 
  A. 2n+m

B. mn − n

C. m + n +3k

D. 0.5*(m + n)

E. 3n + km + m^2

APram · Answer

If A can be multiple of k then D can also be multiple of k. 
Is it that if k = 2, the answer is considering this assumption?

Kindly explain!

Isha2204 · Answer

Try taking k=0.5, m= 1 and n=1.5 and you will be able to eliminate all option except for D

Calculation:

0.5(1+1.5) =1.25, this is not a multiple of 0.5

Aabhash777 · Answer

Let us suppose:
m = a.k
n = b.k 
Then

A. 2n+m = 2ak+bk = K * certain value

B. mn - m = (ak bk) - ak = K^2 * Certain value - k *certain value

C. Likewise others will be multiple of K

yazlal25 · Answer

Assume k = 3, n = 6 and m = 9

All options except D would turn out to be multiples of 3. 
Option D = 0.5 * (6+9) = 7.5 which is not a multiple of 3.

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