Answer
(a)$3R$, (b)$\frac{3}{2}R$, (d) $\frac{2}{3}R$ and (e)$\frac{1}{3}R$
Work Step by Step
We can connect three resistors in four different ways (1) all three in series (2) all three in parallel (3) two in parallel and one in series with the resultant of two (4) two in series and one in parallel with the resultant of two.
The equivalent resistances for these combinations are (1) $ 3R$ (2) $\frac{1}{3}R$ and (3) $\frac{3}{2}R$ (4) $\frac{2}{3}R$
