Answer:
Original Length = L1
Stretched length =L2
From
R = pl/A
R=Resistance
p=Resistivity
A=Cross-sectional Area
l= length of wire
We can see that Resistance is directly Proportional to Length... Meaning that Resistance Increases also as Length increases.
R1/L1 = R2/L2
From the question... The key to note is this sentence
"The Stretched length is TWICE the Original Length"
Meaning
L2 = 2L1 (So replace L2 as 2L1 when solving)
R1=20ohms
Let R2 = k
Applying the formula
20/L1 = k/2L1
kL1 = 20x 2 L1
KL1 = 40L1
L1 cancels on both sides
k=40ohms.
So As the length doubled... The Resistance did too
from 20ohms to 40ohms