Answer:
9.6 Ω
Step-by-step explanation:
Notice that this circuit is the same as the one shown in the attached image.
Then we calculate the parallel of R1 and R3 first:
Since R1 = 30 Ω and R2 = 20 Ω, the parallel equivalent of this is 12 Ω and this in series with R5 (4 Ω) is 16 Ω.
Now we calculate the parallel circuit of the three resistors
40 Ω, 60 Ω, and 16 Ω, which gives us: 9.6 Ω