Well it can vary depending on weather, shelter, how active you are, and how hydrated you were at the start, and if you can eat food during this time
Your post reminded of the fate of the crew of the Lady Be Good. A B-24 that was lost in the Libyan desert (April 4, 1943) when it overflew its home base by some 400 miles on the return trip from a mission to Salerno, Italy (from Wikipedia):
“…The diary also says the group survived for eight days in the desert, with only a single canteen of water to share. After walking 130 km (81 mi) from the crash site, the location of the remains of the five airmen shows they had waited behind while the other three (Guy Shelley, “Rip” Ripslinger and Vernon Moore) set off north, to try to find help. The body of S/Sgt Shelley was found 32 km (20 mi) away while 43 km (27 mi) further on were the remains of T/Sgt Ripslinger...”