Question

This has to do with mean,median,mode, and all that stuff, but my teacher is like,not really good at explaining stuff lol

Answer 1

The average of 6 quiz scores, where $x$ is the score of the last quiz, is

$\dfrac{83+81+89+92+80+x}6=\dfrac{425+x}6$

The student needs a minimum average of 86 to earn an A:

$\dfrac{425+x}6=86\implies425+x=516\implies x=91$

so the student needs a score of 91.