Average (mean) = (sum of all the data) / (# of data)

sum of all the data = (average)(# of data)

Thus for 100 students with an average of 93,
sum of all data = (93)(100) = 9300

and for 300 students with an average of 75,
sum of all data = (75)(300) = 22500

Therefore you would expect the overall average to be
(9300 + 22500) / (100 + 300) = 79.5 %

Now if there are x # of advanced students and y # of regular students, then

x + y = 90 (total # of students) and 93x + 75y = 87(x + y) (overall average)

The second equation can be simplified to x - 2y = 0

Subtracting the two equations yields

x = 60 and y = 90

Therefore you would need 60 advanced and 30 regular students.

7 0

3 years ago

I really need the answer immediately!!!!!!!!!

igor_vitrenko [27]

Answer

y = 0.2x − 7

Step-by-step explanation:

Find the slope first by subtracting (10, -5) and (5, -6) in slope formula, this will equal 1/5 or 0.2

Then find the y-intercept which is the point that crosses the y-axis, in this case -7 is the y-intercept

Finally format in y=mx + b for slope-intercept form

y=0.2x-7

5 0

2 years ago