I believe the Lord when He said three days and three nights He would be in the heart of the earth.
 
Matt 12:40 "For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth."
 
 A day has 12 hours, a night has 12 hours. Any way you add it, by the Hebrew calendar or the Gentile calendar, less than 46 hours is NOT 3 days and 3 nights. Friday night and Saturday night are only two nights.