Identify the missing number in the series: 1, 3, 6, 10… - Missing Number (Reasoning) Solved Question

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Q · Missing Numbermedium · 45s

Identify the missing number in the series: 1, 3, 6, 10, ?, 21

TopicMissing Number

Question Typemultiple choice

Difficultymedium

Marking+1 / −0.25

Test Duration30 min

Step-by-Step Solution

Every step explained - no skipped algebra.

The sequence is triangle numbers. The 5th term is 15.

Final Answer: Option A - 15