does sharing broad connection slowers the speed?

Answer 1

Only when the total usage of all networked computers exceeds the total throughput of the broadband connection. .

Answer 2

Broadband connections are vast but limited, but for regular everyday websurfing you could probably have 10 people surfing at once and not notice a slowdown. Its only if someone is downloading something heavyweight, like movies and stuff, that it will start to slow down.