Respuesta :
If Markus wants to use his average score to guess what his 5th score would be he would use the equation for mean to find his 5th test score:
(85 + 92 + 82 + 94) / 4 = average
and the average could give Markus a guess at what his 5th test score might be.
Now if Markus knew his total test average of the 5 tests he wouldn't need to guess, he could just use the mean equation again:
(85 + 92 + 82 + 94 + x) / 5 = y (test score average)
Whether Markus gets his 5th test score(x) or his total test average(y) he can plug in for each variable to find the other.