It is currently 22 Jun 2017, 20:44

GMAT Club Daily Prep

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

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

M7,Q14

Author Message
Senior Manager
Joined: 17 May 2010
Posts: 290
GMAT 1: 710 Q47 V40

Show Tags

07 Aug 2011, 13:13
What is the number of integers from 1 to 1000 (inclusive) that are divisible by neither 11 nor by 35?

884
890
892
910
945
_________________

If you like my post, consider giving me KUDOS!

Senior Manager
Joined: 17 May 2010
Posts: 290
GMAT 1: 710 Q47 V40

Show Tags

07 Aug 2011, 13:17
The explanation says

"To count the number of integers from 1 to $$N$$ (inclusive) that are divisible by $$x$$ , find the value of $$\frac{N}{x}$$ "

But MGMAT says

(Last-First)/Increment + 1.

How come these two are different?

Also in the explanation, the 1000/11 figure is rounded down, even though the number is 90.9. Why not round it up?
_________________

If you like my post, consider giving me KUDOS!

Manager
Joined: 26 Oct 2010
Posts: 82

Show Tags

09 Aug 2011, 15:40
Let's try to understand the logic behind the formula by taking a smaller example. How many nos are there between 1 to9 that are divisible by 2 ?
Going over the multiples of 2 - 2,4,6,8 , i.e. 4
9/2 = 4.5 ...rounds down to 4.
If we round it up, we are including 10 as well. That is why it is important to round down for these examples.

As for the formulae that you have listed, I would use the first formula, the second formula seems to be taken out of context.
Re: M7,Q14   [#permalink] 09 Aug 2011, 15:40
Display posts from previous: Sort by

M7,Q14

Moderator: Bunuel

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.