Answer:
(a) 4.0334Ω
(b)parallel
Explanation:
for resistors connected in parallel;

Req =3.03Ω , R1 =12.18Ω



R2=1/0.2479
R2=4.0334Ω
(b)parallel connection is suitable for the desired total resistance. series connection can not be used to achieve a lower resistance as the equation for series connection is.
Req = R1+R2
Volume = mass / density = 45.6/10.5 = .... L
D is the answer
To get the density you divide mass by volume
So the equation is 400/60=d