How old was Joseph when Rebecca died?

I went to Timeline; the source of these dates is unclear to me, but you asked how to use Logos. Set the filter for Joseph and saw the early date is 1914-1805 BC. Set the filter to Benjamin, get nothing useful. Set the filter to Rachel. I see the early date for the second set of seven years he worked is 1921-1914 BC. So the Logos Timeline seems to think Joseph was conceived when they had been married 7 years (I read the text as saying that Joseph worked 7 years for Leah, married Leah, took a week honeymoon, married Rachel, worked 7 years for Rachel then 7 years for property). So Jacob finished working for Laban in 1907 BC.

Now, since Genesis 35:26 says that all of the children were "begotten" in Paddan-Aram, but Benjamin is actually born in Canaan, Rachel's death must be within 9 months of 1907 BC. In fact, I would say it must be close to that, because she was not visibly pregnant when they left (Genesis 31:35). So let's say Rachel died in 1906 BC, when Joseph was 8. Since Joseph was 30 when he was appointed to Pharaoh's court and Israel's sons came during the 2nd year of the famine, Joseph was 39 when they came. This makes little boy Benjamin, who Israel was so worried about 31 years old, about the same age Jesus was when He began His public ministry.