Modern web browsers make 6 to 8 simultaneous connections to the web server.
The number of simultaneous connections supported by Apache web server is determined by the configuration of the MPM that is used.
Generally the maximum number of users that can access a website served by Apache is equal to ServerLimit * ThreadsPerChild. The ServerLimit is the maximum number of processes that are allowed to be created by Apache. The ThreadsPerChild is the number of threads created per child process