Sex and pregnancy. Help please

Hey ladies so a friend of mine asked if you could have sex with someone and then 6 days later be pregnant. I know that isn't possible but she Won't take my response as an answer. She says that was the first time sleeping with the guy and that he pulled out before hand and literally less than 6 days later she found out she was pregnant. She's younger than me and I think she is a little confused. Can you ladies help me help her lol