Period 1 has 15 students in it and a test average of 86%. Period 2 has 21 students in it and an average of 88%. Period 3 has 12 students in it and an average of 95%. Use weighted means to find the overall average of the classes.
87.3%
88.7%
89.1%
91%

Respuesta :

15+21+12=48 So:1548(0.86)+2148(0.88)+1248(0.95)=? and put it into a decimal!

Answer:

overall average is 89.1%

Explanation:

for period 1, total number of student is 15 and test average is 86%

total mark for period 1 is = 15*86 = 1290

for period 2, total number of student is 21 and test average is 88%

total mark for period 2 is = 21*88 = 1848

for period 3, total number of student is 12 and test average is 95%

total mark for period 3 is = 12*95 = 1140

total mark is  = 1290+1848+1140 = 4278

total student = 15+21+12 =48

overall average is  = 4278/48 = 89.1%