Answer
a. $3.5~\Omega$.
b. $73.5~\Omega$.
c. $66.5~\Omega$.
d. $7~\Omega$.
Work Step by Step
a. The gold fourth band indicates a tolerance of $\pm 5\%$.
$$5\% \times 70\Omega = (0.05)(70\Omega) =3.5\ \Omega .$$
That is, the tolerance is $3.5\ \Omega $.
b. The upper limit is
$$70\ \Omega + 3.5\ \Omega=73.5\ \Omega.$$
c. The lower limit is
$$70\ \Omega - 3.5\ \Omega=66.5\ \Omega.$$
d. The tolerance interval is then $$
73.5\ \Omega-66.5\ \Omega= 7\ \Omega
.$$
