Respuesta :
average=(scores total)/(number of scores)
We are given two averages and two numbers of students so we can calculate the total scores in each class..
75=Ab/40, so the sum of Abraham's class scores is 40(75)=3000 and similarly
81=An/20, so the sum of Anita's class scores is 20(81)=1620
Now we know the total score for all the students is 3000+1620=4620
And we also know that there are a total fo 40+20=60 students, so the overall average for all the students is
a=4620/60=77
We are given two averages and two numbers of students so we can calculate the total scores in each class..
75=Ab/40, so the sum of Abraham's class scores is 40(75)=3000 and similarly
81=An/20, so the sum of Anita's class scores is 20(81)=1620
Now we know the total score for all the students is 3000+1620=4620
And we also know that there are a total fo 40+20=60 students, so the overall average for all the students is
a=4620/60=77