Answer:
By using 4 resistors in parallel and followed by a resistor in series.
Step-by-step explanation:
Let consider 5 resistors with a resistance of 20 ohms each, the total resistance is equal to 25 ohms when the first four resistance are settled in parallel and is followed by a resistor is series. The calculations are presented below:
1st Stage (4 resistors in parallel)

If
, then:



2nd Stage (1 resistor in series)

Now, the equivalent resistance is:


