Inequalities & Modulus for CAT: Formulas, Weightage & Question Types
Modulus equations, maxima and minima, and counting integer solutions.
Inequalities & Modulus formula sheet
Everything CAT needs from Inequalities & Modulus, in one place. Bookmark it for revision; the lesson in the app explains where each line comes from and when to reach for it.
Everything for this chapter, in one place. is real throughout.
Modulus — the basics
| Definition | if , and if |
| Always | and |
| Products | |
| What it means | is the distance from to |
Solving with a modulus
| , | or |
| , | |
| , | or |
| , | no solution |
| needs — check every root against this |
Two moduli
| Triangle inequality | , equal exactly when and have the same sign |
| Reverse form | |
| Sum of two distances | , equal exactly when lies between and |
| Worth memorising |
Sign charts — how every rational inequality is solved
| Method | factor into linear pieces, mark every root and every break, test one point, alternate |
| Odd power of a factor | the sign flips across that root |
| Even power of a factor | the sign does not flip |
| Denominator roots | always excluded, drawn hollow, even when the inequality is or |
| Never do this | cross-multiply by a quantity whose sign you do not know |
AM–GM and friends — for positives
| Two terms | , equal only when |
| The workhorse | for , and for |
| General two-term | for |
| Squares | |
| Fixed sum | the product is largest when the numbers are equal |
| Fixed product | the sum is smallest when the numbers are equal |
| Cauchy–Schwarz | , equal exactly when |
Quadratic maxima and minima — see the Quadratic chapter
| Extreme value of | , reached at |
The 5 Inequalities & Modulus question types CAT repeats
Past CAT papers return to the same few shapes. Learn to recognise them and most questions become a known routine. Beyond these, CAT has asked 3 rarer one-off shapes here.
- 01
A modulus equation — split at the critical points
- 02
Two moduli added — read it as distance
- 03
Find a maximum or a minimum
- 04
A rational or quadratic inequality — chart the signs
- 05
Count the integer solutions
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Inequalities & Modulus in CAT: quick answers
- How many Inequalities & Modulus questions come in CAT Quant?
- About 1.3 questions in a 22-question Quant section, worth roughly 4 marks. Inequalities & Modulus appeared in 21 of the 24 CAT papers from 2017 to 2025, 34 questions in all, which ranks it 4 of 25 Quant chapters.
- Are Inequalities & Modulus questions in CAT MCQ or TITA?
- 38% of the Inequalities & Modulus questions asked since 2017 were TITA (type in the answer, no negative marking). The rest were multiple choice.
- What types of Inequalities & Modulus questions does CAT ask?
- CAT keeps returning to 5 question shapes in Inequalities & Modulus: A modulus equation — split at the critical points; Two moduli added — read it as distance; Find a maximum or a minimum; A rational or quadratic inequality — chart the signs; Count the integer solutions.