Answer:
The resistance R stretched of the wire if it is stretched to twice its original length is [Δ(2L) / A ]* 2
Explanation:
Original Resistance R = ΔL / A
Given length is doubled
New length  L' = 2L
New Volume is constant, resistivity and density of material is also assumed to be constant
AL = A'L'
AL = A'(2L)
A' = AL / 2L
A' = A / 2
∴ new Resistance R' = ΔL' / A'
                 =  Δ(2L) / A/2
                 = [Δ(2L) / A ]* 2
