Question

What is (a) the highest, (b) the lowest total resistance that can be secured
by combinations of four coils of resistances 4 ,8,12,24​

Answer 1

the highest resistance can be obtained only by arranging the resistors in series.

so, R eq (series)= 4+8+12+24

so highest resistance is = 48 ohm

the lowest resistance can obtained only by arranging the resistors in parallel.

so, R eq (parallel= 1/4+1/8+1/12+1/24

so lowest resistance is = 2 ohm