posted by Amy~ .
Going into the final exam which will count as two-thirds of the final grade, Mike has test scores of 86,80,84,and 90. What score does he need on the final to earn an average score of 80?
Is this right:
(86+80+84+90)/4 = 80
or ((86+80+84+90+(2/3x))/5 = 80
the mean of the four test scores is worth 1/3 of his grade while his final is worth 2/3 of his grade
here's how to set it up: