YOU SAID:
I have an exam in eight hours and thirty minutes
INTO JAPANESE
私は8時間30分で試験を受けます
BACK INTO ENGLISH
I take the exam in 8 hours 30 minutes
INTO JAPANESE
8時間30分で受験します
BACK INTO ENGLISH
Take the exam in 8 hours and 30 minutes
INTO JAPANESE
8時間30分で試験を受ける
BACK INTO ENGLISH
Take the exam in 8 hours and 30 minutes
Come on, you can do better than that.