In the following question, four number pairs are given. In each pair the number on left side of (-) is related to the number of the right side of (-) with some Logic/Rule/Relation. Three pairs are similar on basis of same Logic/Rule/Relation. Select the odd one out from the given alternatives. (NOTE : Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g. 13 - Operations on 13 such as adding/ subtracting/multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed)

22 - 40 

The logic followed here is :

(Ist number × 2) - 1  = second number

22 - 40  =  (22 × 2) - 2  = 40 (ODD)

24 - 47  =  (24 × 2) - 1  = 47

18 - 35 = (18 × 2) - 1  = 35

16 - 31 = (16 × 2) - 1  = 31