math
posted by pat on .
if 40 percent of my grade is at a 97 percent average and 40 percent of my grade is at a 92 percent average and my final test is worth 20 percent of the grade then what do i have to score on my final test to have a grade of 91.5 percent or better?

let your final be x
.4(97) + .4(92) + .2x = 91.5
solve for x
I get 79.5 
It certainly pays to check your work! I just took a huge science test. I checked it over twice before I turned it in, and I got an A! My score was 94 out of 100! I figure that each time I checked it, I found half of the mistakes that were there at a time. What would have been my score if I had not checked my work?