Rashi on Genesis 50:3/רש"י על בראשית נ׳:ג׳

1וימלאו לו [AND FORTY DAYS] WERE FULFILLED — They (the physicians) completed the days of embalming until forty days were completed for him.

2ויבכו אתו מצרים שבעים יום AND THE EGYPTIANS WEPT FOR HIM THREESCORE AND TEN DAYS — viz., forty days during the period of embalming and thirty more days for mourning. They wept for him during so long a period because a blessing had come to them on his arrival in Egypt for the famine then ceased and the waters of the Nile again increased (Midrash Tanchuma, Nasso 26).