Letter pair + number: letters move -2, -2 and the number -4

The same question, asked 2 times: 9 Sep 2024 S2*, 23 Sep 2024 S2. Every wording below, oldest first.

Try each one first, then open its answer.

Question 1
9 Sep 2024 S2
24 $Select the option that can replace the question mark (?) in the following series. VO39, TM35, RK31, PI27, ?$
Tap an option to check your answer.
Question 2
23 Sep 2024 S2
16 $Select the term from among the given options that can replace the question mark (?) in the following series. MY 84, KW 80, IU 76, GS 72, ?$
Tap an option to check your answer.