A series is given with one term missing. Choose the correct alternative from…

Concept: In a missing-term number series, take the first term as the given starting value, then find a single rule that generates every following term from its position n = 1, 2, 3, ... (often a fixed relationship combining multiplication and addition, or an equivalent constant common difference); apply that same rule to generate the missing term.

Application: Starting from the given first term 5, and numbering each following term by its position n = 1, 2, 3, 4, the relationship 5n + n generates every one of them:

1. n = 1: 5 x 1 + 1 = 6, the second term (right after the given start).

2. n = 2: 5 x 2 + 2 = 12, the third term.

3. n = 3: 5 x 3 + 3 = 18, the fourth term.

4. n = 4: 5 x 4 + 4 = 24, the missing fifth term.

Cross-check: Viewed as a plain progression, the terms 6, 12, 18 rise by a constant 6 each step, so the next value is 18 + 6 = 24, confirming the result found above.