The answer is 88 if you take the average as the mean. 100 + 90 + 88 + 87 = 365 / 4 is 91.25 which rounds down to 91 percent. If you want to get exactly 91% the answer would be 87 as you do 100+ 90+ 87 + 87 which is 364 / 4 which is 91... Hope this helps!
