Number series – fill in the missing term. Sequence: 0.15, 0.3, __, 1.2, 2.4, …

Introduction / Context:
This sequence scales by a constant ratio (a geometric progression). Recognizing the multiplier and applying it across the blank is the direct route to the answer.

Given Data / Assumptions:

• Sequence: 0.15, 0.3, __, 1.2, 2.4
• 0.3 / 0.15 = 2; 1.2 / (missing) must equal 2; 2.4 / 1.2 = 2.
• Thus the constant ratio is 2.

Concept / Approach:

In a geometric progression, next = current * r for ratio r. With r = 2, keep doubling to move forward, or halving to move backward if needed.

Step-by-Step Solution:

Verification / Alternative check:

All consecutive ratios equal 2 when the blank is 0.6. Therefore, the geometric pattern is consistent throughout.

Why Other Options Are Wrong:

0.9 would require a factor of 3 from 0.3, breaking the pattern. 4.8 is two steps ahead. 0.006 is off by orders of magnitude. Only 0.6 preserves the constant doubling sequence.

Common Pitfalls:

Confusing additive and multiplicative patterns. Always test ratios when a sequence appears to scale up rapidly.

Final Answer:

0.6