Three of the following number pairs are alike in some manner and one is different. Select the odd number pair.
(NOTE: The second number in the given number pairs is formed by performing a certain operation on the first number. The same operation is followed in all the number pairs except one. Find that odd number pair.)
1
55 ∶ 10
2
80 ∶ 13
3
20 ∶ 3
4
95 ∶ 18