What's the difference between なんandなに？
Such as なにを食べますか。なん時に。今日の午後はなんですか。なん歳ですか。それはなんですか。なんの会社ですか。なんで行きますか。なにをしますか。.......they're all written into 何.

Question

Answer

The meanings of both are the same, but the usage is different.

なに　（何） can be on its own and means "what." 
Example: 何をしていますか？ "what are you doing?"

なん　（何）is used as a prefix attached to other words to form a phrase. なん is often used in combination with particles, such as the example you gave above: 何時ですか？= "What time is it?"

Answer

なんandなにmeaning is same. 何時(なん時) is "What time" .今日の午後はなんですか？is...  Sorry I don't understand. なん歳ですかis " how old are you". どのような会社ですか？is " what kind of ~"
 It's okey?