Why is it "el" problema?
Problema is masculine even though it ends in a. You just have to memorize it.
This is a condition, so why shouldn't "estar" be used? "El problema está que no tenemos mucho dinero."
You can say "El problema está en que no tenemos mucho dinero"
Estar form is being marked wrong
Why is "El problema es que no tenemos bastante dinero" wrong?
Can i not use bastante, demasiado or any other adverb of degree instead of "mucho"?
No, because bastante translates to 'enough' or 'sufficient'. Demasiado would be 'too much', etc. Substituting those words alters the meaning of the sentence.
They want you to translate exactly...
Wtf how do we know when a word is maculine when it appears feme?