In the sequence 5, 10, 15, 20, 25, 30, how many times does the number 15 occur?

A. 1

In the sequence 1, 3, 5, 7, 9, 11, how many times does the number 6 occur?

A. 0

In the sequence 12, 15, 18, 21, 24, 27, how many times does the number 21 occur?

A. 1

In a certain language, 'DOG' is coded as 'EPH'. What is the code for 'CAT'?

A. DBU

In the sequence 100, 200, 300, 400, 500, how many times does the number 600 occur?

A. 0