Edit MetaData
8 years, 5 months ago
8 years, 5 months ago
The sum of all co-primes below a given number = E(n)*N/2.
Here E(N) is Euler's Totient Function for that number. So total numbers below 100 which are coprime to 2,3 and 5 is given by
100*1*2*4/(2*3*5) = 20*8/6 = 160/6
So sum of all these numbers = 100*160/12 = 1333
Quick, Easy and Effective Revision
By proceeding you agree to create your account
Free CAT Formulae PDF will be sent to your email address soon !!!