The final exam will count as two tests. Brooke has test scores of 80, 83, 71,61 and 95. What score does Brooke need on the final in order to have an 80?

Question

I thought 80+83+71+61+95 = 390 / 5 = 78

then I don't know what to do next.
Although I did do 78 +2x = 85
and I get 3.5 and the answer is supposed to be 85.

I was wondering what would be the equation?

Answer 1

treat them as two scores and calculate the mean:

(80+83+71+61+95+x+x)/7 = 80