Question

Class A has 21 pupils and class B has 16 pupils. Both classes sit the same maths test. The mean score for class A is 47. The mean score for both classes is 49. What is the mean score (rounded to 2 DP) in the maths test for class B?

Answer 1

33.25

Explanation:

Number of students in class A = 21

Number of students in class B = 16

Mean score for class A = 47

Mean score for class B = ?

Mean score for both classes = 49

mean \: = \frac{ \: sum \: of \: terms}{ \: number \: of \: terms} [/tex]

But sum of terms = mean*number of terms

Hence; sum of terms in class A = mean of A * number of students/ terms in A

sum of terms in class A = 47*21

= 987

number of students/ terms in both class = 21 + 16

= 37

sum of terms in both classes = mean of both classes*number of students/ terms in both classes

sum of terms in both classes = 49*37

=1519

Therefore sum of terms in class B would be

sum of terms in both classes = sum of terms in class A - sum of terms in class B

1519 = 987 - sum of terms in class B

sum of terms in class B = 1519 - 987

sum of terms in class B = 532

THEREFORE; Mean score for class B =

`(sum \: of \: terms \: in \: class \: b\: )/(total \: number \: of \: terms \: in \: class \: b)`

Mean score for class B =

`(532)/(16)`

Mean score for class B = 33.25