Is this "might" a subjunctive?

[nyugaton]

If we don't know the solutions, we might fail in exam.

(1) Is above sentence OK and natural?
(2) Do you consider "might" above a subjunctive?
(3) If the "might" above is a subjunctive, isn't the sentence strange in that the if-clause is a normal condition and the main clause is a subjunctive clause?

[Mister Micawber]

.
Answered HERE.
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[BobK]

Fine, but the example needs a 'the' before 'exam'.

b