Question 208720
Let x,y,z be integers
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let h=3x,,,m=3y,,,n=3z
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hm = (3x)(3y) = 9xy,,,,,therefore  divisible  by  9
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h+m = 3x +3y=3(x+y),,,,,,therefore  not  necessarily divisible  by  9(only3*3,3*6,3*9,etc)
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h+m+n= 3x+3y+3z =3(x+y+z) ,,,,therefore  not  necessarily  divisible  by  9(only3*3,3*6,3*9,etc)
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Therefore  only  (a) is  correct  answer
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