Look at this series: 53, 53, 40, 40, 27, 27, ... What number should come next?

Given data

• Series: 53, 53, 40, 40, 27, 27, ...

Concept/Approach
Numbers repeat in pairs; every new pair starts 13 less than the previous pair's value.

Step-by-Step calculation
53, 53 → 40, 40 (53 − 13)40, 40 → 27, 27 (40 − 13)Next pair value = 27 − 13 = 14 → next term 14

Verification/Alternative
Pattern is: a, a, a−13, a−13, a−26, a−26, ...

Common pitfalls

• Subtracting 13 from each term without noticing the pair repetition.

Final Answer
14