Determine the minimum number of students with scores of 90 required to have the class average over 75. Score 60,70,80,90. Number of students 7, 3, 8, ?
well, with the four scores given, the average is already 75.
I think some info is missing.
To determine the minimum number of students with scores of 90 required to have the class average over 75, we can use the formula for average:
Average = Total sum of scores / Number of students
Given that the scores and number of students for each score level are as follows:
Score | Number of students
60 | 7
70 | 3
80 | 8
90 | ?
To find the minimum number of students with scores of 90 required, we need to determine the missing value for the number of students with a score of 90. Let's assume the missing value is x.
To calculate the total sum of scores, we multiply each score by the number of students and sum them up. We can set up the equation as follows:
(60 * 7) + (70 * 3) + (80 * 8) + (90 * x) = Average * (7 + 3 + 8 + x)
Substituting the given average of 75:
(60 * 7) + (70 * 3) + (80 * 8) + (90 * x) = 75 * (7 + 3 + 8 + x)
Simplifying the equation:
420 + 210 + 640 + 90x = 75 * (18 + x)
1270 + 90x = 75x + 1350
90x - 75x = 1350 - 1270
15x = 80
x = 80 / 15
x = 5.33
Since we can't have a fraction of a student, we can round up the value of x to the nearest whole number. Therefore, the minimum number of students with scores of 90 required to have the class average over 75 is 6.