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CAT 2021 Slot 1 QA Questions & Answer Key

Quantitative Aptitude questions from CAT 2021 Slot 1 (IIM Ahmedabad, Morning Session (8:30 AM – 10:30 AM IST); 22 in the exam) with the answer key and step-by-step solutions

Executive Answer & Section Summary

CAT 2021 Slot 1 Quantitative Aptitude (QA) was conducted by IIM Ahmedabad during the Morning Session (8:30 AM – 10:30 AM 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: 1 November 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 1 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. Q1200
  2. Q270
  3. Q3C
  4. Q4B
  5. Q5B
  6. Q699
  7. Q735
  8. Q8A
  9. Q9A
  10. Q10120
  11. Q11A
  12. Q12B
  13. Q1332
  14. Q14B
  15. Q151000
  16. Q16A
  17. Q17A
  18. Q18A
  19. Q19C
  20. Q20A
  21. Q21B
  22. Q2247
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Official Exam Questions & Explanations (22 of 22)

Sorted in official convenor sequence
Question 1 of 22
CAT 2021 Slot 1QAArithmetic • Mixture & AlligationModerate
The strength of an indigo solution in percentage is equal to the amount of indigo in grams per 100cc100 \mathrm{cc} of water. Two 800cc800 \mathrm{cc} bottles are filled with indigo solutions of strengths 33%33 \% and 17%17 \% , respectively. A part of the solution from the first bottle is thrown away and replaced by an equal volume of the solution from the second bottle. If the strength of the indigo solution in the first bottle has now changed to 21%21 \% then the volume, in cc, of the solution left in the second bottle is
TITA Answer:
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Question 2 of 22
CAT 2021 Slot 1QANumber Systems • MiscellaneousModerate
How many three-digit numbers are greater than 100 and increase by 198 when the three digits are arranged in the reverse order?
TITA Answer:
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Question 3 of 22
CAT 2021 Slot 1QAArithmetic • Ratio, Proportion & VariationEasy
The amount Neeta and Geeta together earn in a day equals what Sita alone earns in 6 days. The amount Sita and Neeta together earn in a day equals what Geeta alone earns in 2 days. The ratio of the daily earnings of the one who earns the most to that of the one who earns the least is
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Question 4 of 22
CAT 2021 Slot 1QAArithmetic • Time & WorkModerate
Anu, Vinu and Manu can complete a work alone in 15 days, 12 days and 20 days, respectively. Vinu works everyday. Anu works only on alternate days starting from the first day while Manu works only on alternate days starting from the second day. Then, the number of days needed to complete the work is
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Question 5 of 22
CAT 2021 Slot 1QAAlgebra • Progression & SeriesModerate
If x0=1,x1=2\mathrm{x}_{0}=1, \mathrm{x}_{1}=2 , and xn+2=1+xn+1xn,n=0,1,2,3……\mathrm{x}_{\mathrm{n}+2}=\frac{1+x_{n+1}}{x_{n}}, n=0,1,2,3 \ldots \ldots., then x2021x_{2021} is
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Question 6 of 22
CAT 2021 Slot 1QAModern Math • LogarithmsModerate
If 5−log⁡105-\log _{10} 1+x+4log⁡10\sqrt{1+x} + 4 \log _{10} 1−x=log⁡1011−x2\sqrt{1-x} = \log _{10} \frac{1}{\sqrt{1- x^{2}}} , then 100x100 \mathrm{x} equals
TITA Answer:
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Question 7 of 22
CAT 2021 Slot 1QAArithmetic • Mean, Median & ModeModerate
Suppose hospital AA admitted 21 less Covid infected patients than hospital BB , and all eventually recovered. The sum of recovery days for patients in hospitals AA and BB were 200 and 152152 , respectively. If the average recovery days for patients admitted in hospital AA was 3 more than the average in hospital BB then the number admitted in hospital AA was
TITA Answer:
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Question 8 of 22
CAT 2021 Slot 1QAAlgebra • ModulusModerate
If r a constant such that ∣x2−4x−13∣=r|x^2 - 4x - 13| = r has exactly three distinct real roots, then the value of r is
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Question 9 of 22
CAT 2021 Slot 1QAArithmetic • Simple & Compound InterestModerate
Anil invests some money at a fixed rate of interest, compounded annually. If the interests accrued during the second and third year are ₹₹806.25806.25 and 866.72,866.72, respectively, the interest accrued, in INR, during the fourth year is nearest to
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Question 10 of 22
CAT 2021 Slot 1QAGeometry • TrianglesModerate
A circle of diameter 8 inches is inscribed in a triangle ABC where ∠ABC=90∘\angle A B C=90^{\circ}. If BC=10B C=10 inches then the area of the triangle in square inches is
TITA Answer:
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Question 11 of 22
CAT 2021 Slot 1QAArithmetic • Time, Speed & DistanceModerate
Two trains cross each other in 14 seconds when running in opposite directions along parallel tracks. The faster train is 160m long and crosses a lamp post in 12 seconds. If the speed of the other train is 6 km/hr less than the faster one, its length, in m, is
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Question 12 of 22
CAT 2021 Slot 1QAAlgebra • Linear EquationModerate
A basket of 2 apples, 4 oranges and 6 mangoes costs the same as a basket of 1 apple, 4 oranges and 8 mangoes, or a basket of 8 oranges and 7 mangoes. Then the number of mangoes in a basket of mangoes that has the same cost as the other baskets is
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Question 13 of 22
CAT 2021 Slot 1QAArithmetic • Time & WorkModerate
Amar, Akbar and Anthony are working on a project. Working together Amar and Akbar can complete the project in 1 year, Akbar and Anthony can complete in 16 months, Anthony and Amar can complete in 2 years. If the person who is neither the fastest nor the slowest works alone, the time in months he will take to complete the project is
TITA Answer:
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Question 14 of 22
CAT 2021 Slot 1QAGeometry • PolygonsEasy
If the area of a regular hexagon is equal to the area of an equilateral triangle of side 12 cm , then the length, in cm , of each side of the hexagon is
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Question 15 of 22
CAT 2021 Slot 1QAArithmetic • Profit & LossModerate
Amal purchases some pens at ₹ 8 each. To sell these, he hires an employee at a fixed wage. He sells 100 of these pens at ₹₹1212 each. If the remaining pens are sold at ₹1111 each, then he makes a net profit of ₹300300 , while he makes a net loss of ₹300300 if the remaining pens are sold at 9 each. The wage of the employee, in INR, is
TITA Answer:
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Question 16 of 22
CAT 2021 Slot 1QAAlgebra • InequalitiesModerate
The number of integers n that satisfy the inequalities ∣n−60∣<∣n−100∣<∣n−20∣|n -60| < |n-100| <| n-20| is
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Question 17 of 22
CAT 2021 Slot 1QAArithmetic • Profit & LossModerate
Identical chocolate pieces are sold in boxes of two sizes, small and large. The large box is sold for twice the price of the small box. If the selling price per gram of chocolate in the large box is 12%12 \% less than that in the small box, then the percentage by which the weight of chocolate in the large box exceeds that in the small box is nearest to
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Question 18 of 22
CAT 2021 Slot 1QAAlgebra • Progression & SeriesModerate
The natural numbers are divided into groups as (1), (2,3,4),(5,6,7,8,9),….(2,3,4),(5,6,7,8,9), \ldots .. and so on. Then, the sum of the numbers in the 15th group is equal to
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Question 19 of 22
CAT 2021 Slot 1QAArithmetic • Mean, Median & ModeModerate
Onion is sold for 5 consecutive months at the rate of Rs 10,20,25,2510,20,25,25 , and 50 per kg, respectively. A family spends a fixed amount of money on onion for each of the first three months, and then spends half that amount on onion for each of the next two months. The average expense for onion, in rupees per kg, for the family over these 5 months is closest to
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Question 20 of 22
CAT 2021 Slot 1QAGeometry • PolygonsModerate
Suppose the length of each side of a regular hexagon ABCDEFABCDEF is 2 cm. It TT is the mod point of CDCD , then the length of ATAT , in cm, is
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Question 21 of 22
CAT 2021 Slot 1QAAlgebra • InequalitiesModerate
f(x)=x2+2x−15x2−7x−18f(x) = \frac{x^2+2x-15}{x^2-7x-18} is negative if and only if
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Question 22 of 22
CAT 2021 Slot 1QAModern Math • Permutation & CombinationModerate
The number of groups of three or more distinct numbers that can be chosen from 1,2, 3,4,5,6,73,4,5,6,7 and 8so that the groups always include 3 and 55 , while 7 and 8 are never included together is
TITA Answer:
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Frequently Asked Questions about CAT 2021 Slot 1 QA Questions & Answer Key

How many questions were asked in CAT 2021 Slot 1 QA?

CAT 2021 Slot 1 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 1 QA?

Achieving a 99.0th percentile in QA required approximately 28–31 marks (~10 net correct), reflecting the moderate difficulty (inaugural 66-question cat blueprint).

Can I practice other sections of CAT 2021 Slot 1?

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 10 QsCAT Algebra PYQs 6 QsCAT Geometry PYQs 3 QsCAT Modern Math PYQs 2 QsCAT Profit, Loss & Discount Questions 2 QsCAT Time and Work & Pipes-Cisterns Questions 2 Qs