Answer:
58.7Ω
Step-by-step explanation:
You want the equivalent resistance of 40Ω in series with the parallel combination of 25.4Ω and 70.8Ω.
Parallel resistors
The equivalent resistance of two parallel resistors, r1 and r2 is ...
req = 1/(1/r1 +1/r2)
For the two given parallel resistors, that is ...
1/(1/25.4 +1/70.8) ≈ 18.69 . . . . ohms
Equivalent resistance
The circuit has a 40Ω resistor in series with this, so the equivalen resistance is ...
40 +18.69 = 58.69Ω ≈ 58.7Ω
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Additional comment
Since the given resistor values are expressed to 0.1 ohms, we have rounded the answer to the same precision. The exact value is 141158/2405 as shown in the calculator display—assuming the given values are exact.