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?
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?
treat them as two scores and calculate the mean:
(80+83+71+61+95+x+x)/7 = 80
To find out what score Brooke needs on the final exam, we first need to calculate her average score from the four tests.
You correctly calculated the sum of the scores: 80 + 83 + 71 + 61 + 95 = 390.
To find the average, we divide the sum by the number of tests: 390 / 5 = 78.
Now, let's set up the equation to find the final exam score required for an average of 80. We know that the final exam counts as two tests, so we can consider it as an additional score to be added to the sum.
Let's represent the unknown final exam score as 'x.' The new average would be (390 + x) / 7, as there would now be a total of 7 scores.
To solve for 'x,' we can set up the equation:
(390 + x) / 7 = 80.
To isolate 'x,' we can cross-multiply and solve for 'x':
390 + x = 80 * 7.
390 + x = 560.
Now, subtract 390 from both sides of the equation:
x = 560 - 390.
x = 170.
Therefore, Brooke needs to score a 170 on the final exam in order to have an 80 average.