Is product 2*x*5*y an even integer?
a.) 2 + x + 5 + y is an even integer
b.) x - y is an odd integer
pls give explanation...
Any number multiplied by 2 is even
hence irrespective of choices we can determine the answer
OOPS silly mistake
i left out possibility of fractions
just occurred to me after seeing the posts
I would re analyse this problem :
consider (1) 2+x+y+5=n n is a even integer => x+y=n-7 => x,y can be fractions or integer => insufficient
consider (2) x-y=m m is odd integer
but here also x,y can be either integer or fraction => insufficient
now consider both (1) and (2) => 2x=m+n-7=> x=(m-7+n)/2 m-7 is even and n is even hence x is integer
also 2y= n-7-m => y=(n-7-m)/2 => m+7 is even n is even hence y is integer
=> 2*x*y*5 is even integer
hence (C) is IMO.
Its Now Or Never