Answer:
[tex]Final\ grade=79.5[/tex]
Step-by-step explanation:
[tex]Homework\ grade=92\\\\quiz\ grade=68\\\\Test\ grade=81\\\\Final\ Grade=10\%\ of\ homework\ grade+20\%\ of\ quizzes\ grade+70\%\ of\ test\ grade\\\\Final\ Grade=\frac{10}{100}\times 92+\frac{20}{100}\times 68+\frac{70}{100}\times 81\\\\Final\ grade=0.1\times 92+0.2\times 68+0.7\times 81\\\\Final\ grade=9.2+13.6+56.7\\\\Final\ grade=79.5[/tex]