In each of the following questions, two numbers are given which follow a certain logical or arithmetic relationship. Identity the same pattern and apply it to find the missing number in the second pair. Choose the correct option from the given alternatives.
15 : 8 : : 31 : ? ​​

Given: 15 : 8 : : 31 : ? ​​

Logic: (1st numbre + 1) $$\div$$ 2 = 2nd number

For, 15 : 8

15 + 1 = 16, 16 $$\div$$ 2 = 8

Similarly,

31 : ?

31 + 1 = 32, 32 $$\div$$ 2 = 16

Thus, correct option is (b).