Data Sufficiency (DS) | Re: Does the integer k have at least three different positive

Simple

St 1

K is multiple of 15

K =5 x 3 x some integer C

Insuff - C could be 1 or many other values

St 2

K is a multiple of 10

K = 5 x 2 x some integer C

Insuff C could be 2 or 1 or many other values

St 1 & 2

Knowing that K is multiple of 15 and 10 just find the LCM and then draw a conclusion

LCM(15,10) = 5 x 3 x 2

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