I answered silently. I heard silence and stayed on the line to see what would happen. After about 25 seconds a young man (20s?) answered with hello - at least 8-10 times. This was definitely a person; not a machine or a recording. There was no background noise. I heard a click but no/no dial tone to indicate he hung up. I remained on the line. About 10 seconds later I heard a busy signal -- not a hang up tone. I hung up. (We receive one silent call almost every day. I wish professional investigators would determine exactly what scams are occurring with many of these calls.)