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:
625
Step-by-step explanation:
it is essentially 5*5*5*5
Answer:
The answer to your question is 3n+5
Answer: 7 laps
Step-by-step explanation:
The athlete planned to run 3 miles
1 lap = 3/7 miles
x laps = 3 miles
by proportion :
x × 3/7miles = 3 miles
x = 3 ÷ 3/7
x = 3 x 7/3
x = 7
Therefore: the athlete will run 7 laps
