Question: When 40! is expressed in base 8 form, what is the last non–zero digit in the base 8 expansion?

A) 2
B) 6
C) 4
D) 2 or 6

For more CAT Level questions in Number Theory visit – https://iim-cat-questions-answers.2iim.com/quant/number-system/factorial/

For CAT level Questions and video solutions – https://online.2iim.com/youtube-cat-live-classes/ and visit https://online.2iim.com/live-classes
For 2IIM Question Bank – http://questions.2iim.com/

Pump up your CAT Preparation with 2IIM Online CAT Course!

Visit https://www.quora.com/What-is-your-review-of-2IIM-Online-CAT-Preparation to know what the students have said.

Go to http://2iim.app/ for an amazing learning experience on your Android phone

Subscribe and Like and Share! Best Wishes.

source

### Fill this form and get best deals on " Coaching classes"

• Get immediate response from the institutes
• Compare institutes and pick only the best!
• Feel free to choose the institute you like, and rest will be taken care of

1. Pradeep kumar 3 years ago

The last digit can be 4,2,8,6 if we multiple odd no to 4 so sir ,how can you say that it is always be 4

2. very good question & even a better explanation sir

3. Sir I solved a bit differently especially in the last part. Sir after getting that 12 zeroes part I surmised that the remaining digits would be a product of four and something odd. Typically (2k+1)*4. Hence 8k+4. Which leads also to the fact that it is in base 8 the 8k will be accommodated in the FIRST section of digits leaving the LAST 13 digits. Hence we are left with only 4 as the possible answer. Overall a very very challenging problem and one people should approach with a very calm and logical mind otherwise leave it entirely. Thank you Sir, for continuing to solve these for us!

4. movies world 3 years ago

Sir how we will solve this

Find remainder when 8^100 is divided by 49

5. shashank goyal 3 years ago

Sir is it a cat level question?

Verify Yourself