What is the value of 87² − 30²?
- A6769
- B6569
- C6669
- D6726
Show answer
Answer: (C) 6669
a² − b² = (a + b)(a − b) = 117 × 57 = 6669.
RRB ALP Number System Questions with Answers & Explanations
20 Number System questions from the Mathematics section of RRB ALP, each with the correct answer and a worked explanation. Try each question first, then tap Show answer to check. When you're ready, take the timed chapter-wise test to see your all-India rank.
What is the square root of 7569?
- A87
- B86
- C89
- D84
Show answer
Answer: (A) 87
87 × 87 = 7569.
What is the unit digit of 27^69?
- A6
- B1
- C5
- D7
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Answer: (D) 7
Unit digits of powers of 7 repeat in a cycle of 4; 69 mod 4 = 1, so the unit digit is 7.
What is the sum of the first 41 natural numbers?
- A861
- B1681
- C820
- D902
Show answer
Answer: (A) 861
Sum = n(n + 1)/2 = 41 × 42/2 = 861.
What is the remainder when 33244 is divided by 9?
- A7
- B1
- C6
- D8
Show answer
Answer: (A) 7
33244 = 9 × 3693 + 7.
What is the remainder when 99718 is divided by 13?
- A8
- B5
- C12
- D7
Show answer
Answer: (A) 8
99718 = 13 × 7670 + 8.
What is the unit digit of 13^40?
- A9
- B7
- C1
- D2
Show answer
Answer: (C) 1
Unit digits of powers of 3 repeat in a cycle of 4; 40 mod 4 = 0, so the unit digit is 1.
What is the HCF of 20 and 28?
- A4
- B8
- C2
- D35
Show answer
Answer: (A) 4
20 = 4 × 5 and 28 = 4 × 7, so HCF = 4.
What is the value of 66² − 26²?
- A1600
- B3780
- C3720
- D3680
Show answer
Answer: (D) 3680
a² − b² = (a + b)(a − b) = 92 × 40 = 3680.
What is the sum of the first 73 natural numbers?
- A2774
- B2701
- C5329
- D2628
Show answer
Answer: (B) 2701
Sum = n(n + 1)/2 = 73 × 74/2 = 2701.
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Timed Mathematics test · 20 questions · instant rank
What is the square root of 196?
- A16
- B13
- C14
- D15
Show answer
Answer: (C) 14
14 × 14 = 196.
What is the remainder when 41126 is divided by 13?
- A7
- B3
- C5
- D4
Show answer
Answer: (A) 7
41126 = 13 × 3163 + 7.
What is the unit digit of 17^37?
- A7
- B6
- C3
- D9
Show answer
Answer: (A) 7
Unit digits of powers of 7 repeat in a cycle of 4; 37 mod 4 = 1, so the unit digit is 7.
What is the HCF of 54 and 72?
- A12
- B54
- C9
- D18
Show answer
Answer: (D) 18
54 = 18 × 3 and 72 = 18 × 4, so HCF = 18.
What is the value of 94² − 27²?
- A8207
- B8174
- C8107
- D8007
Show answer
Answer: (C) 8107
a² − b² = (a + b)(a − b) = 121 × 67 = 8107.
What is the sum of the first 29 natural numbers?
- A464
- B406
- C841
- D435
Show answer
Answer: (D) 435
Sum = n(n + 1)/2 = 29 × 30/2 = 435.
What is the square root of 4624?
- A69
- B68
- C70
- D67
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Answer: (B) 68
68 × 68 = 4624.
What is the remainder when 20672 is divided by 9?
- A8
- B0
- C7
- D6
Show answer
Answer: (A) 8
20672 = 9 × 2296 + 8.
What is the unit digit of 7^34?
- A1
- B8
- C9
- D4
Show answer
Answer: (C) 9
Unit digits of powers of 7 repeat in a cycle of 4; 34 mod 4 = 2, so the unit digit is 9.
What is the value of 76² − 25²?
- A5151
- B2601
- C5202
- D5051
Show answer
Answer: (A) 5151
a² − b² = (a + b)(a − b) = 101 × 51 = 5151.
These are RankerClub practice questions written in the RRB ALP pattern. They are not official SSC/IBPS/RRB papers.
