question #3 Sahih al-Bukhari 5900, Book 77, Hadith 117 : How many white hairs did the Prophet Muhammad (ﷺ) have at the time of his passing according to narrations?

The Prophet (ﷺ) was neither conspicuously tall, nor short; neither, very white, nor tawny. His hair was
neither much curled, nor very straight. Allah sent him (as an Apostle) at the age of forty (and after
that) he stayed for ten years in Mecca, and for ten more years in Medina. Allah took him unto Him at
the age of sixty, and he scarcely had ten white hairs on his head and in his beard.