I have a couple of questions I need your help to find answers to.
1. How long has mankind been on this earth?
2. Is there any information in the Bible to help us answer the above question?
I would really appreciate your help to answer the above questions.
The Bible doesn’t answer your questions directly but you can back into a reasonable estimate. By doing a little research in Genesis you can discover that Abraham was born 1947 years after Adam’s creation (See From Adam To Abraham). When Abraham was 100 his son Isaac was born (Gen. 21:5) and when Isaac was 60 years old Jacob was born (Gen. 25:26). The Lord had told Abraham his descendants would spend 400 years in Egypt, and Jacob was 130 years old when the time in Egypt began (Gen. 47:9) Galatians 3:17 says they were actually there 430 years. By most historical accounts the Exodus took place somewhere 1200-1300 BC. This is consistent with the time of King David’s reign beginning around 1000 BC, the 4th generation after the Israelites conquered Jericho (Ruth 4:21-22). So now we can convert all this to approximate dates. If we take the earlier date for the Exodus and count backwards we discover that Adam was created about 4000 BC.