In the following question, four groups of three numbers are given. In each group the second and third number are related to the first number by a Logic/Rule/Relation. Three are similar on basis of same Logic/Rule/Relation. Select the odd one out from the given alternatives.
Two identical resistors, each of 10 ohm, are connected in parallel. This combination, in turn, is connected to a third resistor of 10 ohm. The equivalent resistance of the combination is ___.