Hey psm12se,
I am also getting the same answer as sana.noor. ie (D). What's the official answer ?
But here is what I did,
So we have to show that k & (l+m) = (k&l) + (k&m) for all numbers k, l, m
and & can be +,- or *
If you check all these three operations in the question stem, you will find that only subtraction ( -) doesn't work. And the addition and multiplication works. ie.
k+ ( l+m) = (k+l) + (k+m)
k* ( l+m) = (k*l) + ( k*m )
but this operation doesn't work with the subtraction. Moreover, if you know.. + and * operations are linear in nature, so it will always follow the distributive rules.
Ok, now going to the options.
ST.1 :-
1) k&1 is not equal to 1 &k for some numbers k.
As we know only operation which doesn't follow this operation is subtraction( - ) , so it is sufficient.
2) & represents subtraction
It just tells us that it is subtraction operation. So, sufficient.
Since both st1 and st2 are sufficient.
We choose D .
Hope this helps
psm12se wrote:Apologies: Posted this question in wrong forum. This question should have been in DS
If & represents one of the operations +, -, and *,
Is k & (l+m) = (k&l) + (k&m) for all numbers k,l, and m?
1) k&1 is not equal to 1 &k for some numbers k.
2) & represents subtraction.
