You start by adding 90 plus 91.6, but since you said you have a 100 in the other 10 percent, you divide 100/10 and get 10. So then you add the 10 to the 90 to make it 100. So now you add 100 + 91.6 an you get 191.6. Then you divide that by two to get the average and its 95.8. I would appreciate if you made this the brainiest answer, hope this helped :)