alleryThe prime factorisation of 1386 is
- 2^2 × 3 × 7 × 11
- 2 × 3^2 × 7 × 11
- 2 × 3^2 × 7 × 13
- 2 × 3 × 7 × 11
Show answer and solution
Correct answer: B. 2 × 3^2 × 7 × 11
1386 = 2 × 693 = 2 × 3 × 231 = 2 × 3^2 × 77 = 2 × 3^2 × 7 × 11.
RRB NTPC Number System — practice questions
Explore 25 free Number System questions in RRB NTPC Mathematics. Open each question or exercise to read its content, reference answers and available explanation.
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Showing questions 1–25 of 25.
The prime factorisation of 1386 isRead the answer and worked solution →Every integer above 1 has a unique factorisation intoRead the answer and worked solution →A number is divisible by 3 when its digit sum is a multiple ofRead the answer and worked solution →What is the cube of negative 3?Read the answer and worked solution →The difference between 7 squared and 6 squared equals which number?Read the answer and worked solution →Which of these numbers is a perfect cube?Read the answer and worked solution →What is the gap between the squares 49 and 36?Read the answer and worked solution →Evaluate the product of three factors each equal to -4.Read the answer and worked solution →Which one of 1, 2, 3 and 5 is the least prime number?Read the answer and worked solution →Which of 13, 17, 19 and 21 has a factor besides 1 and itself?Read the answer and worked solution →What kind of number is formed by summing any two consecutive triangular numbers?Read the answer and worked solution →When divided by 8, what remainder is always left by an odd perfect square?Read the answer and worked solution →The square of any even integer is always divisible by which number?Read the answer and worked solution →RRB NTPC · Match Cubes of NumbersRead the answer and worked solution →Which of the following is the smallest prime number?Read the answer and worked solution →What is the face value of 7 in the number 45,782?Read the answer and worked solution →What is the sum of the first 10 natural numbers?Read the answer and worked solution →Which of the following numbers is divisible by 9?Read the answer and worked solution →What is the place value of 5 in the number 25,489?Read the answer and worked solution →How many prime numbers are there between 1 and 20?Read the answer and worked solution →When a number is divided by 8, the quotient is 12 and remainder is 5. What is the number?Read the answer and worked solution →Which of the following is a composite number?Read the answer and worked solution →RRB NTPC · Classifying Basic NumbersRead the answer and worked solution →RRB NTPC · Integer Divisibility RulesRead the answer and worked solution →RRB NTPC · Number Values and CountsRead the answer and worked solution →
Worked practice questions
Every integer above 1 has a unique factorisation into
- odd numbers
- squares
- even numbers
- primes
Show answer and solution
Correct answer: D. primes
This is the fundamental theorem of arithmetic: unique prime factorisation.
A number is divisible by 3 when its digit sum is a multiple of
- 5
- 9
- 2
- 3
Show answer and solution
Correct answer: D. 3
The digit sum shows divisibility by 3 when it is itself a multiple of 3.
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