Question 992046
Your scores for the first three quizzes are 85, 68, 90, so the total points you have so far is: 

{{{85 + 68 + 90 = 243}}} points

You need at least 320 points, and now you only have 243 points, that means on the last test, you have to get at least 77 points because 

{{{77 + 243 = 320}}}

So the range of scores you can get on the last quiz that will give you an overall B is from 77 to 100

I hope this answer is helpful :)