The resistance of a piece of wire is directly proportional to its length as the wire is cut in two equal parts
Resistance of each part = r/2
We know that in parallel combination equivalent resistance ; R = 1/R1 + 1/R2
So , Here R = 1/ r/2 +1/ r/2
= 2/r + 2/r
Thus, the resistance of the combination is 1/4th of the original resistance.