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.
Answer:
= 105(x+2)/33-x
Step-by-step explanation:
Given the expression
[3(x+2)*10*7]÷70 - 2(x+2)
= 3(x+2)*70÷70 - 2(x+2)
= 210(x+2)/70-2x-4
= 210(x+2)/66-2x
= 210(x+2)/2(33-x)
= 105(x+2)/33-x
Answer:
A is the answer.
Step-by-step explanation:
What you do is you multiply -6 into each of the fractions and then add or minus the fractions together.
-6(1/4x)=-3/2x
-6(-2/3x)=4x
-6(5/6x)=-5x
-3/4x+4x-5x=-2.5 or A.
Answer:
5y + 15
Step-by-step explanation:
8y - 6y = 2y + 3y = 5y
13 + 2 = 15
