Question

only for intelligents baccha log ..​

Answer 1

you need to apply formula of series and parallel carefully.

first 2.5 and 10 in parallel

the answer of the same in series with 10 ohm.

asnwer of the above in parallel with 12

answer of the above in series with 10

now answer of the above in parallel with 16.

(secret hint- just stretch a and b to the farthest point in mind and solve whatever is between them.