Question

How can three resistors of resistances 2 ohm, 3 ohm and 5 ohm be connected to get a total resistance of 3.875ohm and 0.9 ohm

Answer 1

for effective resistance to be 3.875
connect 5ohm and 3 ohm resistors in parallel and in series with 2 ohm resistor
and for 0.9 ohm connect all resistors in parallel
that's the answer hope it helps you

Answer 2

if we connect all three in parallel we will get equalent resistent as 0.9 ohm
if we connect 3ohm and 5ohm in parallel and 2ohm in series we get 3.875