Multiply your 80 by 6. 480. That’s what your total needs to be to average a C. Your current scores total 412. So, you’d need a 68 to average 80%.

Substitute in whatever a C actually is for 80, and work the same way.

After the next quiz, there will be six grades. When you add up those six grades and divide by 6, the answer will have to be 75 or more.

Now let’s work backwards. 75 times 6 is 450, so the total of the six grades will have to be 450. Add the first five grades together and subtract that total from 450. The answer will be the grade she needs on the last quiz.

Sometimes teachers aren’t bad at teaching — they just want to see if you can think for yourself instead of being spoon-fed the answers like a mother feeding a baby.

equation is this:

In this equation, x is what you want to find (The grade she needs).

(88 + 84 + 92 + 63 + 85 + x)/6 = 80

412 + x = 480

in this equation x would be 68 only!

Therefore the answer is 68%!

(I said used “80” as a C grade, because I don’t know what you consider a C….. =])

HOPE THAT HELPS!!! =]