Question

What is the highest and the lowest total resistance that can be secured by combination of four coils of resistance 4ohm,8ohm,12ohm,24ohm

Answer 1

Here's your answer in the pic

Answer 2

Highest resistance is always obtained in series combination.

Therefore highest will be:

Rs= (4+8+12+24) ohm = 48 ohm

Lowest resistance is always in parallel combination.

Therefore lowest will be:

1/Rp= (1/4+1/8+1/12+1/24) ohm = 12/24 ohm = 1/2 ohm

therefore Rp= 2ohm