Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 350,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Nos. divided by 3 between 100 and 999 (including); starting 102,105....till 999 are {(999-102=897/3)+1 }=300 Therefore, nos. not divided by 300 between 100 & 999 = {(total nos between 100&999 ) minus nos. divided by 3}= [ {(999-100)+1}-300]=600

Ans-B _________________

" Make more efforts " Press Kudos if you liked my post

Number of 3 digit numbers = 9(Hundreds's digit should be between 1-9)*10(ten's digit can be anything from 0-9)*10(Unit's digit can be anything from 0-9)= 900

All 900 numbers are in an order.i.e 100 to 999. Every 3rd number is divisible by 3.

Hence, numbers divisible by 3 = 900/3 = 300, other 600 are not divisible.

1) Every 1-in-3 integers is divisible by 3. (Every third number....) 2) In Total there are 900 3 digit numbers (100 to 999) 3) 1/3 rd of 900 are divisible by 3 --> 2/3 rd of 900 not divisible = 600 integers of 3 digit size not divisible by 3!

The way I approached this, is not basically using counting more along the principles of divisibility.

y = nx === if 'y' is divisible by 'x' then, that equation holds, where n is the number times it can be divided by 'x'.

So with that in mind largest 3 digit number = 999, divisibility by '3' => y = nx => 999 = n * 3 => n = 333 Similarly largest 2 digit number = 99, divisibility by 3 => 99= n*3 => n = 33

Hence the difference will give the number of the factors between 999 and 99 => 333-33 = 300

But it asks for number which isn't divisibile by 3 instead, hence total 3 digit numbers - number of factors of 3 = 900-300 = 600

Similarly if we do this for number 5 instead, it becomes: Largest three digit number divisible by 5 = 995; hence quotient = 995/5 => 199 Largest two digit number divisible by 5 = 95 ; hence quotient = 95/5 => 19

Hence number of factors between 995 and 95 = 199-19 => 180 Numbers that aren't divisible by 5 = 900-180 => 720