Question 93779
Let x=sum of the scores of the remaining students 


First write the percentages in decimal form by dividing by 100:

81 percent={{{81/100=0.81}}}

27 percent={{{27/100=0.27}}}


{{{(0.27+x)/10=0.81}}} Set up the equation which represents the average (note: the average can be found by adding up everyone's scores and dividing that sum by the number of students who took the test)


{{{0.27+x=8.10}}} Multiply both sides by 10


{{{x=7.83}}} Subtract 0.27 from both sides



So the sum of the scores for the remaining 9 students is 7.83. Now divide this sum by 9 to find the new average



{{{7.83/9=0.87}}}


Now multiply 0.87 by 100 to get a percentage


{{{0.87*100=87}}}


So the new average is 87%