CAT Arithmetic: Syllabus, Topics, Weightage & Strategy

Arithmetic has been the most consistently large QA bucket in recent CAT papers; recent slots commonly carry roughly 7–9 arithmetic questions. For CAT preparation, the useful question is not “Have I finished the chapter?” but can I recognise the version of the concept CAT hides inside a word problem and choose an efficient method under time pressure?

What to know

The core checklist for this topic is: Percentages, ratio & proportion, averages, profit-loss-discount, simple & compound interest, mixtures/alligation; and time-speed-distance, time & work, pipes/cisterns, weighted averages. Learn these as connected ideas rather than isolated formulas. CAT often combines two of them in one question.

Recurring CAT-style forms

Expect questions built around Reverse percentages, chained percentage change, ratio after addition/removal, weighted average/replacement, markup-discount-profit chains, and relative speed. The wording changes, but the mathematical structure repeats. Your first 20–30 seconds should be spent identifying that structure before writing equations.

Decision rules worth remembering

• Translate words to ratios quickly
• use base-100 when appropriate
• convert between fraction/percentage/ratio
• compare rates instead of quantities
• build equations only after simplifying the story

One original example

A product rises from ₹500 to ₹600 and then falls 10%. The final price is ₹540, so the net change from ₹500 is +8%, not +10%. The calculation forces you to respect the changing percentage base.

The point of a worked example is not the answer; it is the choice of representation. After solving, ask whether a ratio table, base-100 assumption, sign chart, factorisation or diagram made the work shorter.

Common traps

• Using simple average instead of weighted average
• adding percentage changes directly
• confusing speed ratio with time ratio
• using selling price as base for profit%
• treating combined work rates as time sums

These traps are valuable because they explain why a student can “know the formula” and still lose marks. Add the exact mistake to your error log when it occurs; do not simply write “silly mistake.”

How to practise

Start with 10–15 untimed questions until the first step becomes automatic. Then use mixed timed sets where this topic is not announced in advance. Finish with sectionals and mock review. Mastery checkpoint: Can solve a mixed 8-question arithmetic drill in ~20 minutes with at least 75–80% accuracy and explain why each chosen method was efficient.

Once that checkpoint is stable, move on rather than over-polishing one chapter. CAT QA is a portfolio of scoring areas; the objective is enough reliable topics to make question selection easy on exam day.