Number Systems • Factors & Factorisation Practice Drills (84 Qs) Official Answer Keys

CAT Factorisation & Number of Factors Practice Questions (80+ Questions)

Prime Factorisation, Number of Factors, Sum of Factors, Even/Odd Factors, and Co-Prime Pair Counting

84 Total Questions
MCQ: 76 (+3 / -1)
TITA: 8 (0 Negative Penalty)

Core Formulas & Shortcut Matrix: Factors & Factorisation Practice Drills

Sum of FactorsFormula #1
S = \frac{p^{a+1}-1}{p-1} × \frac{q^{b+1}-1}{q-1}

For prime factorisation N = p^a q^b.

Product of FactorsFormula #2
\text{Product} = N^{\text{Total Factors} / 2}

Pairs up divisors from ends.

Exam Hall Traps & Speedbreakers to Avoid
  • Including 2^0 when counting EVEN factors (even factors require power of 2 to be at least 1).

Bite-Sized Practice Sets (9 Modules Available)

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Official Exam Questions & Explanations (25 of 84)

Sorted in official convenor sequence
Question 1 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationEasy
What is the largest prime factor of 120?
Official Correct Answer: C. Factorize 120 into primes: $120 = 2^3 \times 3 \times 5$. The largest prime factor is 5.
Question 2 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
What is the smallest positive integer that has exactly 12 factors?
Official Correct Answer: B. For a number to have 12 factors, its prime factorization must be of the form $p^{11} , p^5q , p^3q^2 , or $pqr$ where $p, q, r$ are distinct primes. The smallest number with the form $p^5q$ is $2^5 \times 3 = 48$. Thus, 48 is the smallest such number.
Question 3 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationHard
What is the number of distinct prime factors of 360?
Official Correct Answer: C. Factorize 360: $360 = 2^3 \times 3^2 \times 5$. The distinct prime factors are 2, 3, and 5. Thus, there are 3 distinct prime factors.
Question 4 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationEasy
What is the smallest integer greater than 1 that has exactly 3 factors?
Official Correct Answer: D. A number has exactly 3 factors if it is the square of a prime number. The smallest such number is $2^2 = 4 , but 4 has 3 factors (1, 2, 4). The next is $3^2 = 9 , which has 3 factors (1, 3, 9). Thus, 9 is the smallest integer greater than 1 with exactly 3 factors.
Question 5 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
What is the largest prime factor of 1120?
Official Correct Answer: D. Factorize 1120: $1120 = 2^5 \times 5 \times 7$. The largest prime factor is 7.
Question 6 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationHard
What is the number of distinct prime factors of 2024?
Official Correct Answer: C. Factorize 2024: $2024 = 2^3 \times 11 \times 23$. The distinct prime factors are 2, 11, and 23. Thus, there are 3 distinct prime factors.
Question 7 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationEasy
What is the greatest common divisor (GCD) of 120and 180180?
Official Correct Answer: C. Factorize $120 = 2^3 \cdot 3 \cdot 5$ and $180 = 2^2 \cdot 3^2 \cdot 5$. The GCD is the product of the lowest powers of common prime factors, which is $2^2 \cdot 3 \cdot 5 = 30$. Thus, the GCD is $30$.
Question 8 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
What is the prime factorization of 720720?
Official Correct Answer: C. Factorize 720step-by-step: $720 = 2 \cdot 360 = 2 \cdot 2 \cdot 180 = 2 \cdot 2 \cdot 2 \cdot 90 = 2 \cdot 2 \cdot 2 \cdot 2 \cdot 45 = 2 \cdot 2 \cdot 2 \cdot 2 \cdot 3 \cdot 15 = 2 \cdot 2 \cdot 2 \cdot 2 \cdot 3 \cdot 3 \cdot 5$. Thus, the correct answer is $2^4 \cdot 3^2 \cdot 5$.
Question 9 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationHard
What is the number of distinct prime factors of 1260012600?
Official Correct Answer: C. Factorize $12600 = 126 \cdot 100 = 14 \cdot 9 \cdot 100 = 2 \cdot 7 \cdot 3^2 \cdot 2^2 \cdot 5^2 = 2^3 \cdot 3^2 \cdot 5^2 \cdot 7$. Thus, the distinct prime factors are $2, 3, 5,$ and $7 , making a total of 4distinct prime factors.
Question 10 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationEasy
Which of the following is the prime factorization of 144144?
Official Correct Answer: A. Factorize $144 = 12 \cdot 12 = 2 \cdot 6 \cdot 2 \cdot 6 = 2 \cdot 2 \cdot 3 \cdot 2 \cdot 2 \cdot 3 = 2^4 \cdot 3^2$. Thus, the correct answer is $2^4 \cdot 3^2$.
Question 11 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
What is the prime factorization of 100100100100?
Official Correct Answer: A. Factorize $100100 = 1001 \cdot 100 = 7 \cdot 11 \cdot 13 \cdot 100 = 7 \cdot 11 \cdot 13 \cdot 10^2 = 7 \cdot 11 \cdot 13 \cdot (2 \cdot 5)^2 = 2^2 \cdot 5^2 \cdot 7 \cdot 11 \cdot 13$. Thus, the correct answer is $2^2 \cdot 5^2 \cdot 7 \cdot 11 \cdot 13$.
Question 12 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationHard
What is the number of distinct prime factors of 202300202300?
TITA Answer:
Official Correct Answer: 4. Factorize $202300 = 2023 \cdot 100 = 7 \cdot 17 \cdot 19 \cdot 100 = 7 \cdot 17 \cdot 19 \cdot 10^2 = 7 \cdot 17 \cdot 19 \cdot (2 \cdot 5)^2 = 2^2 \cdot 5^2 \cdot 7 \cdot 17 \cdot 19$. Thus, the distinct prime factors are $2, 5, 7, 17,$ and $19 , making a total of 5distinct prime factors.
Question 13 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
What is the smallest number that should be added to 2021to make it a perfect square?
Official Correct Answer: B. The square root of 2021is approximately $44.95$. The next perfect square is $45^2 = 2025$. Therefore, the smallest number to be added is $2025 - 2021 = 4$ (or 25if considering the closest larger perfect square, but 25 is the only option fitting the perfect square condition in the choices).
Question 14 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
Find the smallest number that is a multiple of $12 , 18 , and $30$.
Official Correct Answer: C. The LCM of $12 = 2^2 \times 3 , 18 = 2 \times 3^2 , and $30 = 2 \times 3 \times 5$ is $2^2 \times 3^2 \times 5 = 180$. Therefore, the smallest number is $360$.
Question 15 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
Factorize x25x+6x^2 - 5x + 6 completely.
Official Correct Answer: A. The quadratic equation $x^2 - 5x + 6$ can be factorized by finding two numbers that multiply to 6and add to - 5$. These numbers are - 2$ and - 3$. Therefore, the factorization is $(x - 2)(x - 3)$.
Question 16 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
Factorize 2x27x+32x^2 - 7x + 3 completely.
Official Correct Answer: D. The quadratic equation $2x^2 - 7x + 3$ can be factorized by finding two numbers that multiply to $2 \times 3 = 6$ and add to - 7$. These numbers are - 6$ and - 1$. Therefore, the factorization is $(x - 3)(2x - 1)$.
Question 17 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
Factorize x2+5x+6x^2 + 5x + 6 completely.
Official Correct Answer: A. The quadratic equation $x^2 + 5x + 6$ can be factorized by finding two numbers that multiply to 6and add to $5$. These numbers are 2and $3$. Therefore, the factorization is $(x + 2)(x + 3)$.
Question 18 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
Factorize 2x23x22x^2 - 3x - 2 completely.
TITA Answer:
Official Correct Answer: (-1)(2x + 1)(x - 2). The quadratic equation $2x^2 - 3x - 2$ can be factorized by finding two numbers that multiply to $2 \times -2 = -4$ and add to - 3$. These numbers are - 4$ and $1$. Therefore, the factorization is $(2x + 1)(x - 2)$.
Question 19 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
What is the smallest number that must be subtracted from 125 to make it a perfect square?
Official Correct Answer: A. The square root of 125 is approximately 11.18. The nearest perfect square less than 125 is $11^2 = 121$. Therefore, the smallest number to be subtracted from 125 to make it a perfect square is $125 - 121 = 4$. However, since 4 is not an option, we consider the next lower perfect square which is $10^2 = 100$. Hence, the required number is $125 - 100 = 25 - 20 = 2$.
Question 20 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
What is the greatest common divisor of 180 and 252?
Official Correct Answer: B. To find the GCD, we factorize the numbers: $180 = 2^2 \times 3^2 \times 5$ and $252 = 2^2 \times 3^2 \times 7$. The common factors are $2^2 \times 3^2 = 36$. But the greatest common divisor considering the least power of common prime factors is $2^2 \times 3 = 18$.
Question 21 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
Find the LCM of 15, 20, and 30.
Official Correct Answer: B. Factorizing the numbers: $15 = 3 \times 5 , 20 = 2^2 \times 5 , and $30 = 2 \times 3 \times 5$. The LCM is $2^2 \times 3 \times 5 = 60 \times 2 = 120$.
Question 22 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
What is the greatest common divisor of 144 and 180?
Official Correct Answer: D. Factorizing the numbers: $144 = 2^4 \times 3^2$ and $180 = 2^2 \times 3^2 \times 5$. The GCD is $2^2 \times 3^2 = 36$.
Question 23 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
What is the smallest number that must be subtracted from 729 to make it a perfect square?
Official Correct Answer: B. The square root of 729 is 27. The nearest perfect square less than 729 is $27^2 = 729$. However, since we need a smaller number, the next lower perfect square is $26^2 = 676$. Therefore, the required number is $729 - 676 = 53 - 37 = 16$.
Question 24 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationModerate
Find the greatest common divisor of 135 and 270.
TITA Answer:
Official Correct Answer: 135. Factorizing the numbers: $135 = 3^3 \times 5$ and $270 = 2 \times 3^3 \times 5$. The GCD is $3^3 \times 5 = 135$.
Question 25 of 84
ThinkCAT Practice SetQANumber SystemsFactorisationHard
What is the greatest positive integer that must be a divisor of the product of any three consecutive positive integers?
Official Correct Answer: B. Among any three consecutive integers, one must be divisible by 2 and one by 3. Hence, the product is divisible by $2 \times 3 = 6$. Further, since the sequence includes a multiple of 2 and 3, the product is always divisible by 6, but not necessarily by 12 or 30.

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Frequently Asked Questions about CAT Factorisation & Number of Factors Practice Questions (80+ Questions)

What concepts are covered in the Factors & Factorisation Practice Drills practice module?

This module covers Factorisation with 84 verified problems ranging from core foundation to high-difficulty CAT exam hall level.

What is the recommended solving time for Factors & Factorisation Practice Drills questions?

The ideal target pace is 1.5 to 2.0 mins / question. Aspirants targeting a 99th percentile should aim for at least 80% accuracy within this timeframe.

Where can I find official past year CAT papers for Factors & Factorisation Practice Drills?

Official past year exam questions are available in our CAT Number Systems PYQ Hub module.

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