CAT 2022 Slot 3 QA Q17 Progressions & Series

Question 17 of the Quantitative Ability (QA) section, CAT 2022 Slot 3, with CAT's official answer and a worked solution.

The average of all 3-digit terms in the arithmetic progression 38, 55, 72, ..., is

TITA: type in the answer. There are no options and no negative marking.

Answer: 548 Progressions & Series TITA

Solution

  1. Terms are \(38+17k\). First 3-digit term: \(k=4\) gives 106.
  2. Last 3-digit term: \(17k\le961\Rightarrow k=56\), giving \(38+952=990\).
  3. Average of an AP's terms \(=\frac{106+990}2=548\).

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