In Heidi's history class, the only grades that count toward the semester average are the $6$ tests she has already taken and the upcoming final exam. The final exam counts as two tests. Heidi has determined that if she earns $99$ points on the final she will have exactly a $90$-point average for the semester. On average, how many points has Heidi scored on each test prior to the final exam?
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
In Heidi's history class, the only grades that count toward the semester average are the $6$ tests she has already taken and the upcoming final exam. The final exam counts as two tests. Heidi has determined that if she earns $99$ points on the final she will have exactly a $90$-point average for the semester. On average, how many points has Heidi scored on each test prior to the final exam?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
87
In Heidi's history class, the only grades that count toward the semester average are the $6$ tests she has already taken and the upcoming final exam. The final exam counts as two tests. Heidi has determined that if she earns $99$ points on the final she will have exactly a $90$-point average for the semester. On average, how many points has Heidi scored on each test prior to the final exam?
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