Hi Rudy..
u give good question, here in Indonesia, sometimes we don't know the different between that words "Mengapa" dan " Kenapa"
Those words is same formal words in Indonesia Language, but from that words its gonna use properly if we know what kind of sentences that we want to make and for what. In dictionary thats words have same meaning "why". See the ex. below :
- Mengapa kesalahpahaman memicu terjadinya perselisihan (Why
misunderstanding trigger disputes)
- Ada suatu keadaan. Seorang anak kecil tiba tiba marah dan menagis, kemudian
ibunya bertanya "Kenapa menagis" (TIn one situation. There was a child,
suddenly become angry and cry, and her/his mother asking "why u cray dear?" )
So from that ex u can know the different "Mengapa " more often use in formal situation such as in letters or journalistic world and "Kenapa" often to use in daily conversation that sometimes we don't need formal words.
Well hope can helping u to understand about "Mengapa" and "Kenapa" using on sentences