00:01
In this problem, we have been given a student's quiz scores for four quizzes, and we need to determine what score the student needs on the fifth quiz to have a mean score of 87 % if all of the quizzes have equal weights.
00:15
So according to the question, we need the mean to be 87%.
00:21
And 87 % is 87 by 100, which is 0 .87.
00:27
Now, the mean, this over here, it is said that all of the quizzes have equal weight.
00:33
So the mean will simply be the sum of all of the scores divided by the number of scores.
00:40
And we want the mean for five quizzes, so the number of scores will be five.
00:45
And in the numerator, we need the sum of all of the quiz scores.
00:48
So the first quiz score is 89%, that's 89 by 100 or 0 .89.
00:53
The second quiz score is 90 % at 0 .90.
00:57
The third quiz score is 82%.
00:59
That's 0 .82.
01:01
The next quiz score is 77 % that's 0 .77...