SSC CGL Number System Questions
15 questions on Number System for SSC CGL, including questions from 2024 and 2023 papers. Each comes with the correct answer and a worked explanation.
- Questions
- 15
- Moderate
- 15
Number System questions with solutions
The HCF and LCM of two numbers are 11 and 231 respectively. If one of the numbers is 33, what is the other number?
- (A)88
- (B)66
- (C)7
- (D)77
Show answer and explanation
Correct answer: (D) 77
For any two numbers, product of the numbers = HCF × LCM. So the other number = (11 × 231) ÷ 33 = 2541 ÷ 33 = 77.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 8 and 48 respectively. If one of the numbers is 16, what is the other number?
- (A)16
- (B)3
- (C)32
- (D)24
Show answer and explanation
Correct answer: (D) 24
For any two numbers, product of the numbers = HCF × LCM. So the other number = (8 × 48) ÷ 16 = 384 ÷ 16 = 24.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 3 and 90 respectively. If one of the numbers is 15, what is the other number?
- (A)21
- (B)18
- (C)6
- (D)15
Show answer and explanation
Correct answer: (B) 18
For any two numbers, product of the numbers = HCF × LCM. So the other number = (3 × 90) ÷ 15 = 270 ÷ 15 = 18.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 9 and 108 respectively. If one of the numbers is 27, what is the other number?
- (A)27
- (B)45
- (C)4
- (D)36
Show answer and explanation
Correct answer: (D) 36
For any two numbers, product of the numbers = HCF × LCM. So the other number = (9 × 108) ÷ 27 = 972 ÷ 27 = 36.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 6 and 72 respectively. If one of the numbers is 18, what is the other number?
- (A)30
- (B)4
- (C)18
- (D)24
Show answer and explanation
Correct answer: (D) 24
For any two numbers, product of the numbers = HCF × LCM. So the other number = (6 × 72) ÷ 18 = 432 ÷ 18 = 24.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 5 and 105 respectively. If one of the numbers is 15, what is the other number?
- (A)7
- (B)40
- (C)35
- (D)30
Show answer and explanation
Correct answer: (C) 35
For any two numbers, product of the numbers = HCF × LCM. So the other number = (5 × 105) ÷ 15 = 525 ÷ 15 = 35.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 2 and 80 respectively. If one of the numbers is 10, what is the other number?
- (A)18
- (B)16
- (C)14
- (D)8
Show answer and explanation
Correct answer: (B) 16
For any two numbers, product of the numbers = HCF × LCM. So the other number = (2 × 80) ÷ 10 = 160 ÷ 10 = 16.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 3 and 42 respectively. If one of the numbers is 6, what is the other number?
- (A)24
- (B)21
- (C)7
- (D)18
Show answer and explanation
Correct answer: (B) 21
For any two numbers, product of the numbers = HCF × LCM. So the other number = (3 × 42) ÷ 6 = 126 ÷ 6 = 21.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 3 and 36 respectively. If one of the numbers is 9, what is the other number?
- (A)15
- (B)4
- (C)12
- (D)9
Show answer and explanation
Correct answer: (C) 12
For any two numbers, product of the numbers = HCF × LCM. So the other number = (3 × 36) ÷ 9 = 108 ÷ 9 = 12.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 3 and 63 respectively. If one of the numbers is 9, what is the other number?
- (A)18
- (B)21
- (C)24
- (D)7
Show answer and explanation
Correct answer: (B) 21
For any two numbers, product of the numbers = HCF × LCM. So the other number = (3 × 63) ÷ 9 = 189 ÷ 9 = 21.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 7 and 245 respectively. If one of the numbers is 35, what is the other number?
- (A)7
- (B)56
- (C)49
- (D)42
Show answer and explanation
Correct answer: (C) 49
For any two numbers, product of the numbers = HCF × LCM. So the other number = (7 × 245) ÷ 35 = 1715 ÷ 35 = 49.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 5 and 140 respectively. If one of the numbers is 20, what is the other number?
- (A)40
- (B)30
- (C)7
- (D)35
Show answer and explanation
Correct answer: (D) 35
For any two numbers, product of the numbers = HCF × LCM. So the other number = (5 × 140) ÷ 20 = 700 ÷ 20 = 35.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 4 and 24 respectively. If one of the numbers is 8, what is the other number?
- (A)8
- (B)12
- (C)16
- (D)3
Show answer and explanation
Correct answer: (B) 12
For any two numbers, product of the numbers = HCF × LCM. So the other number = (4 × 24) ÷ 8 = 96 ÷ 8 = 12.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 2 and 40 respectively. If one of the numbers is 8, what is the other number?
- (A)12
- (B)10
- (C)5
- (D)8
Show answer and explanation
Correct answer: (B) 10
For any two numbers, product of the numbers = HCF × LCM. So the other number = (2 × 40) ÷ 8 = 80 ÷ 8 = 10.
Shortcut: Other number = HCF × LCM ÷ given number.
The HCF and LCM of two numbers are 5 and 30 respectively. If one of the numbers is 10, what is the other number?
- (A)15
- (B)3
- (C)20
- (D)10
Show answer and explanation
Correct answer: (A) 15
For any two numbers, product of the numbers = HCF × LCM. So the other number = (5 × 30) ÷ 10 = 150 ÷ 10 = 15.
Shortcut: Other number = HCF × LCM ÷ given number.
Frequently asked questions
How many SSC CGL Number System questions can I practise here?
15 questions — 15 moderate. 15 are shown on this page with answers and explanations, and the practice set draws from all of them.
How should I practise Number System for SSC CGL?
Read through a few solved questions first to see the method, then take a timed practice set. Afterwards, check which questions you got wrong or spent longest on and redo those before moving on.