Differences are multiples of 5 (+5, +10, +15, ...): find the term

The same question, asked 2 times: 12 Sep 2024 S1*, 23 Sep 2025 S3. Every wording below, oldest first.

Try each one first, then open its answer.

Question 1
12 Sep 2024 S1
15 $Select the number from the given options to complete the series. 25, 30, 40, 55, 75, ___$
Tap an option to check your answer.
Question 2
23 Sep 2025 S3
4 $What should come in place of the question mark '?' in the following number series? 9, 14, 24, 39, 59, ?, 114$
Tap an option to check your answer.