The second number in the given number pairs is obtained by performing certain mathematical operation(s) on the first number. The same operation(s) are followed in all the number pairs, EXCEPT one. Find that odd number pair.

30 : 80

The logic followed here Is :

(Ist number) × 3 = second number

50 : 150 = 50 × 3 = 150

30 : 80 = 30 × 3 = 90 ≠ 80 Odd

40 : 120 = 40 × 3 = 120

20 : 60 = 20 × 3 = 60