Identify the missing number in the series: 100, 90, 80, 70, ?, 50.

A. 60

Which pair of numbers is the odd one out?

C. 2, 4

In the sequence A, B, C, ?, E, F, what character should replace the question mark?

A. D

If the word 'CAT' is coded as 3120, what is the code for 'DOG'?

A. 4157

Which of the following numbers is the odd one out?

C. 10