All Exams Test series for 1 year @ ₹349 only
Question

The number of prime numbers lying between 306 and 313, both included, is:

This question was previously asked in
RRB NTPC 2024 CBT 1 Question Paper (28-Aug-2025) (Shift 3)
The correct answer is
3

Identifying Prime Numbers Between 306 and 313

The problem asks for the count of prime numbers within the range of 306 to 313, inclusive.

Step 1: List the numbers in the range.
The numbers to consider are: 306, 307, 308, 309, 310, 311, 312, 313.

Step 2: Define a prime number.
A prime number is a natural number greater than 1 that has exactly two distinct positive divisors: 1 and itself.

Step 3: Check each number for primality.

  • 306: Divisible by 2 (it's even). Not prime.
  • 307: Not divisible by 2, 3 (sum of digits is 10), 5. Test divisibility by primes up to $\sqrt{307} \approx 17.5$ (i.e., 7, 11, 13, 17). 307 is not divisible by any of these. Prime.
  • 308: Divisible by 2 (it's even). Not prime.
  • 309: Divisible by 3 (sum of digits is 12). Not prime.
  • 310: Divisible by 2 and 5 (ends in 0). Not prime.
  • 311: Not divisible by 2, 3 (sum of digits is 5), 5. Test divisibility by primes up to $\sqrt{311} \approx 17.6$ (i.e., 7, 11, 13, 17). 311 is not divisible by any of these. Prime.
  • 312: Divisible by 2 (it's even). Not prime.
  • 313: Not divisible by 2, 3 (sum of digits is 7), 5. Test divisibility by primes up to $\sqrt{313} \approx 17.7$ (i.e., 7, 11, 13, 17). 313 is not divisible by any of these. Prime.

Step 4: Count the prime numbers found.
The prime numbers identified in the range are 307, 311, and 313.

Conclusion: There are 3 prime numbers between 306 and 313, inclusive.

Was this answer helpful?

Similar Questions

  1. The number of prime numbers lying between 389 and 403, both included, is:
  2. The number of prime numbers lying between 488 and 494, both included, is:
  3. The sum of the first six prime numbers is:
  4. Which of the following is a prime number?
  5. How many prime numbers are there that are less than 50?
  6. In four consecutive prime numbers, the product of the last three is 7429 and that of the first three is 4199. The largest of these prime number is:
  7. The sum of the first four prime numbers is:
  8. How many of the integers between $109$ and $121$, both inclusive, are prime numbers?
  9. If $a : b = 3 : 4$ and $d : b = 4 : 3$, then find the ratio of a to d.
  10. Which one of the following numbers is NOT a prime number?

Important Questions from Prime Numbers

  1. The number whose only factors are 1 and the number itself is called a/an ________ number.

  2. Consider the following numbers :

    1. 437

    2. 797

    3. 1073

    How many of the above numbers are prime ? 

  3. What are the total prime numbers from 1 to 100?

  4. How many prime numbers are there between 20 and 50?

  5. How many prime numbers are there between 100 and 120?

Need Expert Advice?
Upcoming Exams
RRB ALP
July 28, 2026
RRB Group D
August 03, 2026
Test Series
RRB NTPC img
Railways
RRB NTPC Under Graduate 2026 New Mock Test Series
1459 Tests 2 Tests Free
215 Attempts
4.3(512)
English, Hindi, Telugu +7 More

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App