Solved

Need help in equation

Posted on 2011-09-06
8
324 Views
Last Modified: 2012-05-12
Hi guys: Can any one please help me in that question ? Thanks.

How many integers in the set {n belongs to Z | 1 less than equals to n less than equals to 700} are divisible to 2 or 7 ?

0
Comment
Question by:mustish1
  • 3
  • 3
  • 2
8 Comments
 
LVL 37

Expert Comment

by:TommySzalapski
ID: 36490263
Well, since this question has an academic nature to it...
How many are divisible by 2 (easy)
How many are divisible by 7 (also easy)
How many are divisible by both (not too hard)

Once you have those, the answer should be pretty easy to come up with (please no one jump in with just the answer).
0
 
LVL 8

Accepted Solution

by:
stalhw earned 300 total points
ID: 36490285
1 less than equals to n less than equal to 700
that doesn't make sense...
you probably meant
1 <= n <= 700
So the set is integers from 1 to 700 ?
then it shouldn't be too hard...

one in seven will be divisible by 7... so 100
one in 2 is divisible by 2... so 350
0
 
LVL 37

Assisted Solution

by:TommySzalapski
TommySzalapski earned 200 total points
ID: 36490309
Remember from set theory A or B = A + B - (A and B)
0
Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

 

Author Comment

by:mustish1
ID: 36490311
1 <= n <= 700
divisible to 2 and 7

k. just divide 700/2 and divide 700/7

its easy thanks.
0
 
LVL 37

Expert Comment

by:TommySzalapski
ID: 36490333
Yes, but the answer is not 350 + 100 = 450 because if you do that, you'll count some twice. (i.e. 14 is divisible by both and is counted twice).
0
 
LVL 8

Expert Comment

by:stalhw
ID: 36490349
oh he meant disisible by both?
well half of the divisible by 7 will also be divisible by 2....
(7,14,21,28,35,42,etc easy to see that half are pair)

so 50 will be divisible by both
0
 
LVL 8

Expert Comment

by:stalhw
ID: 36490357
and if you want divisible by 2 OR 7,
just remove the 50 that are divisible by both... so 350+100-50 = 400
0
 

Author Comment

by:mustish1
ID: 36490383
ok thanks
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Complete list of Microsoft tech support phone numbers 5 128
Fix Xerox ColorQube 9303 copier 94-613 error code 1 197
URL to download QuickBooks Pro 2013 2 73
English question 2 20
Finding a job can be stressful - searches, resume tweaks, and networking events can be super boring. Luckily we're here to help you land your dream job!
If you get continual lockouts after changing your Active Directory password, there are several possible reasons.  Two of the most common are using other devices to access your email and stored passwords in the credential manager of windows.
Saved searches can save you time by quickly referencing commonly searched terms on any topic. Whether you are looking for questions you can answer or hoping to learn about a specific issue, a saved search can help you get the most out of your time o…
Where to go on the main page to find the job listings. How to apply to a job that you are interested in from the list that is featured on our Careers page.

809 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question