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

The LCM of two prime numbers $x$ and $y$ ($x > y$) is 319. The value of $2x - 5y$ is:

This question was previously asked in
RRB NTPC 2019 CBT 1 Question Paper (8-Mar-2021) (Shift 2)
The correct answer is
3

Identify Prime Factors of LCM

The question states that the LCM of two prime numbers, $x$ and $y$, where $x > y$, is 319. Since $x$ and $y$ are distinct prime numbers, their LCM is simply their product.

Therefore, we need to find the prime factors of 319.

We can test small prime numbers to find the factors of 319:

  • $319 \div 11 = 29$

Both 11 and 29 are prime numbers.

Determine Values of x and y

We found the prime factors of 319 are 11 and 29. The question specifies that $x > y$. Assigning the larger factor to $x$ and the smaller factor to $y$:

  • $x = 29$
  • $y = 11$

Calculate the Expression 2x - 5y

Now substitute the values of $x$ and $y$ into the expression $2x - 5y$:

$2x - 5y = 2(29) - 5(11)$

Calculate the terms:

  • $2 \times 29 = 58$
  • $5 \times 11 = 55$

Perform the subtraction:

$58 - 55 = 3$

The value of the expression $2x - 5y$ is 3.

Was this answer helpful?

Similar Questions

  1. Which of the following is a prime number?
  2. The sum of the first four prime numbers is:
  3. 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:
  4. How many of the integers between $109$ and $121$, both inclusive, are prime numbers?
  5. The sum of the first six prime numbers is:
  6. If $a : b = 3 : 4$ and $d : b = 4 : 3$, then find the ratio of a to d.
  7. Consider the following statements and decide which of them is/are correct.

    1) Every prime is odd.
    2) Product of any two prime numbers is odd.
  8. Which of the following numbers is NOT prime?
  9. Which one of the following numbers is NOT a prime number?
  10. Which of the following numbers is prime?

Important Questions from Prime Numbers

  1. Which of the following is NOT a pair of co-prime numbers?

  2. a and b are two positive integers such that the least prime factor of a is 2 and the least prime factor of b is 5. Then the least prime factor of a + b is

  3. If product of two prime numbers A and B (A < B) is 221, then what is the value of (4A – 3B)?

  4. Sum of all the prime numbers between 70 and 100 is :

  5. Which of the following is a prime number?

Need Expert Advice?
Upcoming Exams
RRB JE
October 27, 2026
RRB ALP
November 03, 2026
Test Series
RRB NTPC img
Railways
RRB NTPC Under Graduate 2026 New Mock Test Series
1612 Tests 1 Tests Free
691 Attempts
4.3(510)
English, Hindi, Telugu +7 More
More Questions from RRB NTPC

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