Best Answer - Chosen by the Asker
어디있는지 is "where it is"
Tell me where it is
->어디있는지 나에게 말해줘
The sentence that you suggest is polite expression. so It's a little bit long.
If you wanna ask it to your friend,
You just say
"가까운 은행이 어디있어?"
"Gakkaun eunhaeing-i eodi it-so?"
Where is the nearest bank?