Ahmed has scored 819 total points in the class thus far because 9 x 91 = <<9*91=819>>819
Emily had scored 828 total points before the final assignments because 9 x 92 = <<9*92=828>>828
She scored 918 total points after the final assignment because 828 + 90 = <<828+90=918>>918
Ahmed needs to score a 99 to tie Emily for the semester because 918 - 819 = <<918-819=99>>99
Ahmed needs to score a 100 to beat Emily for the semester because 99 + 1 = <<99+1=100>>100
#### 100