An electronics student is prototyping a sensor circuit and has access to exactly three identical 18 Ω resistors.
Which of the following equivalent resistance values can the student not achieve by combining all three resistors in a single network?
6 Ω6\ \Omega6 Ω
12 Ω12\ \Omega12 Ω
24 Ω24\ \Omega24 Ω
27 Ω27\ \Omega27 Ω