Question

On a certain exam, Tony corrected 20 papers and found the mean for his group to be 60. Alive corrected the remaining 10 papers and found that the mean for her group was 50. What is the mean of the combined group of 30 students?

Answer 1

The mean of the combined group of 30 students is equal to 56.67

Explanation:

Let

x ----> The sum of the notes of the 20 papers

y ----> The sum of the notes of the 10 papers

we know that

60=x/20 -----> x=60*20=1,200

50=y/10 -----> y=50*10=500

The mean of the combined group of 30 students is equal to

(x+y)/30

substitute

(1,200+500)/30=56.67