A number series is given below with one missing term. Choose the correct alternative from the given options that will complete the series. -0.5, -0.35, -0.2, -0.05, ?, 0.25

Introduction / Context:
This question tests understanding of simple arithmetic progressions in decimal form within a number series. The learner has to observe how each term changes and then use that pattern to find the missing value in a sequence that moves from negative decimals toward a positive value. Such items are very common in reasoning examinations because they check pattern recognition and accuracy with decimal calculations.

Given Data / Assumptions:
- The given series is: -0.5, -0.35, -0.2, -0.05, ?, 0.25. - There is one missing term in the fifth position. - The pattern is expected to be consistent across consecutive terms.

Concept / Approach:
The idea is to compute the difference between each pair of consecutive terms and see whether these differences follow a simple arithmetic pattern. If the same constant value is added each time, then the series is an arithmetic progression, only written with decimal numbers. Once the constant difference is identified, the missing term can be found by adding this difference to the previous term, or by working backward from later terms.

Step-by-Step Solution:
Step 1: Find the difference between the first and second term: -0.35 - (-0.5) = -0.35 + 0.5 = 0.15. Step 2: Find the difference between the second and third term: -0.2 - (-0.35) = -0.2 + 0.35 = 0.15. Step 3: Find the difference between the third and fourth term: -0.05 - (-0.2) = -0.05 + 0.2 = 0.15. Step 4: The series therefore increases by 0.15 at every step. Step 5: The missing fifth term equals the fourth term plus 0.15: -0.05 + 0.15 = 0.10. Step 6: The sixth term also fits this rule: 0.10 + 0.15 = 0.25.

Verification / Alternative check:
To verify, start from the first term and repeatedly add 0.15. You obtain -0.5, -0.35, -0.2, -0.05, 0.10, 0.25. This exactly matches the given series when the missing term is taken as 0.1. The uniform increase of 0.15 confirms that the pattern is a simple arithmetic progression in decimal form with constant difference 0.15.

Why Other Options Are Wrong:
- Option -0.1 would create a difference of 0.1 from -0.05, which breaks the constant step of 0.15. - Option 0.15 would create a difference of 0.2 from -0.05, again not equal to 0.15. - Option -0.15 moves the series backward and would not move the sequence toward the given positive value 0.25.

Common Pitfalls:
Many learners focus only on the signs and may confuse negative values, leading them to subtract instead of adding the common difference. Another frequent mistake is to approximate or round differences too early instead of computing them exactly. Always compute the exact decimal difference between consecutive terms before deciding on the pattern.

Final Answer:
The missing term in the series is 0.1, so the correct option is 0.1.