Two numbers are said to be 'relatively prime' if their greatest common factor is 1. How many integers greater than 10 and less than 30 are relatively prime with 28?

 Feb 2, 2021

i think that you could go through every number, but first, you should eliminate some of the obvious numbers. this way, you'll be able to go through the numbers you are looking through and count those.


i started by eliminating all of the even numbers, as those will all share a factor with 28, since 28 is divisible by 2.


then i eliminated 21 and 28. 


now you are left with -


11, 13, 15, 17, 19, 23, 25, 27, and 29. 


so, there are 9 integers.


hope this helped!

 Feb 2, 2021
edited by macar0ni  Feb 2, 2021
edited by macar0ni  Feb 2, 2021

That's the wrong answer

vockeyvockvock  Feb 2, 2021

Hi :)))


macar0ni seems to have edited his/her/their answer, and 9 is the correct one now. 

It is quite disheartening when people respond with "That's the wrong answer" or simply doesn't respond. 

Often times, the people responding are other students who are busy and want to help others.

It gets quite frustrating when it feels like other people aren't appreciating your time and effort to help them. 

While you can do what you like, it doesn't hurt to respond with a bit more appreciation, even if the answer is incorrect. 


And thank you macar0ni for giving your time to help others. :))))



catmg  Feb 3, 2021
edited by catmg  Feb 3, 2021


Well said, cat, and I agree with you 100%.  Another thing that bugs me is when someone just posts the answer without showing how to obtain that answer.  I can't figure what they're thinking, maybe just showing off, but one thing that's for sure they aren't trying to help. 


Guest Feb 3, 2021

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