The day of Pentecost took place 50 days after Easter Sunday, which is traditionally thought to be the day that Christ rose from the dead. Christ himself said He would be three days and three nights in the heart of the earth. Now if you look into this for yourself, instead of blindly believing what people tell you, it will be clear that it is impossible to fit three full days and nights into the period between Friday afternoon, and early Sunday morning.
People often confuse tradition with what the bible actually says, and that is one of the reasons why people think the bible contains errors. It doesn’t, but people’s traditions do. I found a good site with some interesting information about Pentecost: