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CAT 2021 Slot 3 QA Questions & Answer Key

Quantitative Aptitude questions from CAT 2021 Slot 3 (IIM Ahmedabad, Evening Session (4:30 PM – 6:30 PM IST); 22 in the exam) with the answer key and step-by-step solutions

Executive Answer & Section Summary

CAT 2021 Slot 3 Quantitative Aptitude (QA) was conducted by IIM Ahmedabad during the Evening Session (4:30 PM – 6:30 PM IST). The section comprised 22 questions administered under a strict 40-minute sectional countdown. Sectional marking adheres to standard CAT conventions: +3 marks for every correct answer, -1 mark penalty for incorrect MCQs, and zero penalty for non-MCQ TITA questions. Securing a 99.0th percentile in this section required approximately 28–31 marks (~10 net correct). The question distribution featured comprehensive quantitative problem sets covering arithmetic (TSD, work, percentages), algebra (quadratics, polynomials, logarithms), and geometry mensuration. All questions in this archive are sourced from official candidate response sheets, cross-verified with the convenor master key, and solved with step-by-step logic proofs on ThinkCAT.

22 Total Questions
MCQ: 14 (+3 / -1)
TITA: 8 (0 Negative Penalty)
Attempt QA Section in Timed 40-Min ModeSolve Questions on this Page

CAT Direct Answer Fact Sheet & Citation Summary

Structured Knowledge Graph • Verified Academic Analysis
Updated for CAT 2026: 31 October 2026
Verified Questions
22 Qs
14 MCQ + 8 TITA
99%ile Score Benchmark
28–31 Marks (out of 66 in QA, ~10 net correct questions)
Scoring Scheme
+3 / -1 / 0
Zero penalty on TITA
Testing Interface
TCS iON CBT
On-Screen Calc Enabled
IIM Exam Strategy & Score Maximization Directives
1Prioritize high-yield arithmetic & algebra questions first to secure the 85th percentile sectional cutoff in the first 20 minutes.
2TITA questions carry zero negative penalty (0 marks for wrong answers); attempt all TITA questions before the sectional timer runs out.
3Use the on-screen digital calculator only for complex 3-digit divisions; mental math approximations save 35–45 seconds per question.
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Editorial & Academic Authority: Verified by ThinkCAT Academic & Editorial Council.
Citation Format: ThinkCAT Academic Archive (thinkcat.in)

CAT 2021 Slot 3 QA Answer Key

Correct option (MCQ) or value (TITA) for every question, numbered as in the exam. Full solutions are in the questions below.

QA

  1. Q13000
  2. Q292
  3. Q3C
  4. Q4D
  5. Q534
  6. Q6A
  7. Q712
  8. Q8C
  9. Q9B
  10. Q10A
  11. Q116
  12. Q12A
  13. Q13B
  14. Q14B
  15. Q15D
  16. Q16D
  17. Q173500
  18. Q18B
  19. Q198
  20. Q20D
  21. Q21C
  22. Q2250
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Official Exam Questions & Explanations (22 of 22)

Sorted in official convenor sequence
Question 1 of 22
CAT 2021 Slot 3QAArithmetic • Time & WorkEasy
Anil can paint a house in 12 days while Barun can paint it in 16 days. Anil, Barun, and Chandu undertake to paint the house for ₹ 24000 and the three of them together complete the painting in 6 days. If Chandu is paid in proportion to the work done by him, then the amount in INR received by him is
TITA Answer:
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Question 2 of 22
CAT 2021 Slot 3QAArithmetic • Mean, Median & ModeModerate
The arithmetic mean of scores of 25 students in an examination is 5050. Five of these students top the examination with the same score. If the scores of the other students are distinct integers with the lowest being 3030 , then the maximum possible score of the toppers is
TITA Answer:
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Question 3 of 22
CAT 2021 Slot 3QAAlgebra • Linear EquationHard
A shop owner bought a total of 64 shirts from a wholesale market that came in two sizes, small and large. The price of a small shirt was INR 50 less than that of a large shirt. She paid a total of INR 5000 for the large shirts, and a total of INR 1800 for the small shirts. Then, the price of a large shirt and a small shirt together, in INR, is
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Question 4 of 22
CAT 2021 Slot 3QAArithmetic • PercentagesModerate
The total of male and female populations in a city increased by 25%25 \% from 1970 to 19801980.During the same period, the male population increased by 40%40\% while the female population increased by 20%20\%. From 1980 to 19901990 , the female population increased by 25%25 \%. In 19901990 , if the female population is twice the male population, then the percentage increase in the total of male and female populations in the city from 1970 to 1990 is
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Question 5 of 22
CAT 2021 Slot 3QAAlgebra • PolynomialsModerate
A tea shop offers tea in cups of three different sizes. The product of the prices, in INR, of three different sizes is equal to 800800. The prices of the smallest size and the medium size are in the ratio 2:52 : 5. If the shop owner decides to increase the prices of the smallest and the medium ones by INR 6 keeping the price of the largest size unchanged, the product then changes to 3200.3200. The sum of the original prices of three different sizes, in INR, is:
TITA Answer:
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Question 6 of 22
CAT 2021 Slot 3QAArithmetic • Mixture & AlligationModerate
If a certain weight of an alloy of silver and copper is mixed with 3 kg of pure silver, the resulting alloy will have 90%90\% silver by weight. If the same weight of the initial alloy is mixed with 2 kg of another alloy which has 90%90\% silver by weight, the resulting alloy will have 84%84\% silver by weight. Then, the weight of the initial alloy, in kg, is
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Question 7 of 22
CAT 2021 Slot 3QAAlgebra • InequalitiesHard
The number of distinct pairs of integers (m,n)(m, n) satisfying ∣1+mn∣<∣m+n∣<5|1 + mn| < |m + n| < 5 is
TITA Answer:
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Question 8 of 22
CAT 2021 Slot 3QAArithmetic • Profit & LossModerate
One part of a hostel's monthly expenses is fixed, and the other part is proportional to the number of its boarders. The hostel collects 1600 per month from each boarder. When the number of boarders is 5050 , the profit of the hostel is 200 per boarder, and when the number of boarders is 7575 , the profit of the hostel is 250 per boarder. When the number of boarders is 8080 , the total profit of the hostel, in INR, will
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Question 9 of 22
CAT 2021 Slot 3QAGeometry • QuadrilateralsHard
Let ABCDABCD be a parallelogram. The lengths of the side ADAD and the diagonal ACAC a 10 cm and 20 cm, respectively. If the angle ∠ADC\angle ADC is equal to 30∘30^\circ then the area of the parallelogram, in sq. cm, is
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Question 10 of 22
CAT 2021 Slot 3QAAlgebra • FunctionsModerate
If f(x)=x2−7xf(x)= x^{2} - 7 x and g(x)=x+3g(x)=x+3 , then the minimum value of f(g(x))−3xf(g(x))-3 x is
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Question 11 of 22
CAT 2021 Slot 3QAAlgebra • Progression & SeriesModerate
If n is a positive integer such that (107)(107)2…(107)n>999(\sqrt[7]{10})(\sqrt[7]{10})^{2} \ldots(\sqrt[7]{10})^{n}>999 , then the smallest value of n is
TITA Answer:
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Question 12 of 22
CAT 2021 Slot 3QAArithmetic • PercentagesModerate
In a tournament, a team has played 40 matches so far and won 30%30 \% of them. If they win 60%60 \% of the remaining matches, their overall win percentage will be 50%50 \%. Suppose they win 90%90 \% of the remaining matches, then the total number of matches won by the team in the tournament will
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Question 13 of 22
CAT 2021 Slot 3QAGeometry • QuadrilateralsModerate
The cost of fencing a rectangular plot is 200 per ft along one side, and 100 per ft along the three other sides. If the area of the rectangular plot is 60000sq. ft, then the lowest possible cost of fencing all four sides, in INR, is
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Question 14 of 22
CAT 2021 Slot 3QAArithmetic • Time & WorkModerate
One day, Rahul started a work at 9AM and Gautam joined him two hours later. They then worked together and completed the work at 5PM the same day. If both had started at 9AM and worked together, the work would have been completed 30 minutes earlier. Working alone, the time Rahul would have taken, in hours, to complete the work is
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Question 15 of 22
CAT 2021 Slot 3QAAlgebra • ModulusModerate
If 3x+2∣y∣+y=73x + 2|y|+ y = 7 and x+∣x∣+3y=1x + |x|+ 3y = 1 , then x+2yx + 2y is
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Question 16 of 22
CAT 2021 Slot 3QAArithmetic • Simple & Compound InterestModerate
Bank AA offers 6%6 \% interest rate per annum compounded half yearly. Bank BB and Bank CC offer simple interest but the annual interest rate offered by Bank CC is twice that of Bank ₹BB. Raju invests a certain amount in Bank B for a certain period and Rupa invests 10,00010,000 in Bank CC for twice that period. The interest that would accrue to Raju during that period is equal to the interest that would have accrued had he invested the same amount in Bank AA for one year. The interest accrued, in INR, to Rupa is
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Question 17 of 22
CAT 2021 Slot 3QAGeometry • QuadrilateralsModerate
A park is shaped like a rhombus and has area 96sq m. If 40m of fencing is needed to enclose the park, the cost, in INR, of laying electric wires along its two diagonals, at the rate of 125 per m, is
TITA Answer:
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Question 18 of 22
CAT 2021 Slot 3QAAlgebra • Progression & SeriesModerate
Consider a sequence of real number x1,x2,x3,...x_1, x_2, x_3, ... such that xn+1=xn+n−1x_{n+1} = x_n + n - 1 for all n≥1n \ge 1. If x1=−1x_1 = -1 then x100x_{100} is equal to
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Question 19 of 22
CAT 2021 Slot 3QAArithmetic • Time, Speed & DistanceModerate
Mira and Amal walk along a circular track, starting from the same point at the sometime. If they walk in the same direction, then in 45 minutes, Amal completes exactly 3 more rounds than Mira. If they walk in opposite directions, then they meet for the first time exactly after 3 minutes. The number of rounds Mira walks in one hour is
TITA Answer:
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Question 20 of 22
CAT 2021 Slot 3QAGeometry • TrianglesHard
In a triangle ABC, ∠\angle BCA = 50∘50^\circ. D and E are points on AB and AC, respectively, such that AD = DE. If F is a point on BC such that BD = DF, then ∠\angle FDE , in degrees, is equal to
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Question 21 of 22
CAT 2021 Slot 3QAModern Math • LogarithmsModerate
For a real number aa , if log⁡15a+log⁡32a(log⁡15a)(log⁡32a)=4\frac{\log _{15} a+\log _{32} a}{\left(\log _{15} a\right)\left(\log _{32} a\right)}=4 then a must lie in the range.
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Question 22 of 22
CAT 2021 Slot 3QAModern Math • Permutation & CombinationModerate
A four-digit number is formed by using only the digits 1,21 , 2 and 3 such that both 2 and 3 appear at least once. The number of all such four-digit numbers is
TITA Answer:
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Frequently Asked Questions about CAT 2021 Slot 3 QA Questions & Answer Key

How many questions were asked in CAT 2021 Slot 3 QA?

CAT 2021 Slot 3 QA contained 22 questions convened by IIM Ahmedabad. Marking was +3 marks for correct answers, -1 for incorrect MCQs, and zero penalty for TITA questions.

What score was required for a 99th percentile in CAT 2021 Slot 3 QA?

Achieving a 99.0th percentile in QA required approximately 28–31 marks (~10 net correct), reflecting the moderate to high difficulty (multi-condition dilr, tough modern math).

Can I practice other sections of CAT 2021 Slot 3?

Yes! You can explore the full paper or switch directly to DILR, VARC, or QA using the related sectional links below.

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Topics in this paper

CAT Arithmetic PYQs 9 QsCAT Algebra PYQs 7 QsCAT Geometry PYQs 4 QsCAT Modern Math PYQs 2 QsCAT Percentages & Change Multiplier Questions 2 QsCAT Time and Work & Pipes-Cisterns Questions 2 Qs