Question

Let pqr be a three digit number. Then, pqr + qrp + rpq will not be always divisible by:

  • 9
  • 37
  • 3
  • p + q + r

✨ Free AI Tools for You

Powered by Chatterbot AI

Answer


The correct option is A (9).

Given a three-digit number $$ pqr $$, we can express the permutations as follows:

$$ \begin{aligned} & pqr = 100p + 10q + r \ & qrp = 100q + 10r + p \ & rpq = 100r + 10p + q \end{aligned} $$

To find the sum of these permutations, we add them together:

$$ \begin{aligned} pqr + qrp + rpq &= (100p + 10q + r) + (100q + 10r + p) + (100r + 10p + q) \ &= 100p + 10q + r + 100q + 10r + p + 100r + 10p + q \ &= 111p + 111q + 111r \ &= 111(p + q + r) \end{aligned} $$

Since we have:

$$ 111(p + q + r) = 3 \times 37 \times (p + q + r) $$

This implies that $$ pqr + qrp + rpq $$ is always divisible by 3, 37, and (p + q + r).

However, this sum is not guaranteed to be divisible by 9 unless $$ (p + q + r) $$ is divisible by 9. Thus, the correct answer is 9.


Was this helpful?

India's 1st AI Doubt Solver for CBSE, JEE, and NEET

Ask a Question for Free

and then it's just ₹212 a month

Learn how Chatterbot AI can help you succeed

Cover Image of the article Computer Science Class 11 CBSE - The Ultimate Guide with Notes, Solutions and AI

Computer Science Class 11 CBSE - The Ultimate Guide with Notes, Solutions and AI

This ultimate guide for CBSE Computer Science class 11 has detailed notes, NCERT solutions, cheat sheets, and our free AI-powered doubt-solving assistant, Chatterbot AI.

Cover Image of the article JEE Advanced 2024 Exam Date Announced: Complete Guide to Eligibility, Syllabus, and Preparation Tips

JEE Advanced 2024 Exam Date Announced: Complete Guide to Eligibility, Syllabus, and Preparation Tips

JEE Advanced 2024 on May 26! Get exam schedule, syllabus, prep tips & more in this guide. Ace India's top engineering test with topper strategies.

Cover Image of the article How to Crack NEET: The Ultimate Blueprint to Outsmart the Exam and Unlock Your Medical Dreams

How to Crack NEET: The Ultimate Blueprint to Outsmart the Exam and Unlock Your Medical Dreams

Ace NEET with expert strategies: Discover effective exam strategies, time management, core concepts mastery, problem-solving techniques, revision tips, and AI-assisted doubt clearing with Chatterbot AI.

Cover Image of the article How to Crack IIT: Smart Self-Study Strategies and AI Tools for Success

How to Crack IIT: Smart Self-Study Strategies and AI Tools for Success

Ace IIT JEE in 6 months without coaching. Discover expert self-study strategies for Physics, Chemistry, and Math. Master time management, mock tests, and leverage AI tools like Chatterbot AI for personalized doubt-solving.