Question

The students in Class A and in Class B take the same examination. There are 28 students in Class A and 32 students in Class B. The mean score for all the students in both classes is 72.6 The mean score for the students in Class A is 75 Work out the mean score for the students in Class B.

Answer 1

Answer:

Step-by-step explanation:

Given :

28 Students in Class A

32 Students in Class B

Mean of Class A and B is 72.6

Mean of Class A is 75.

Procedure :

1] Let x1,x2,x3...x28 be the students of Class A

Hence $\frac{x1 + x2 + x3 +...x28}{28}$ = 75

⇒ x1 + x2 + x3 +...x28 = (28 × 75) =2100  -------- $Eq_{1}$

2] Let y1,y2,y3,...y32 be the students of Class B

Hence $\frac{(x1 + x2 + x3 +...x28) + (y1 + y2 + y3 +...y32)}{28+32}$ = 72.6

⇒ x1 + x2 + x3 +...x28 + y1 + y2 + y3 +...y32 = (60 × 72.6) =4356 ------- $Eq_{2}$

3] $Eq_{2} - Eq_{1}$ ⇒ y1 + y2 + y3 +...y32 = 4356 - 2100 = 2256 ----$Eq_{3}$

Dividing both sides of $Eq_{3}$ by 32 :

$\frac{y1 + y2 + y3 +...y32}{32}$ = $\frac{2256}{32}$ = 70.5

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Answer 2

Answer:

70.5

Step-by-step explanation:)

(28 + 32) * 72.6 = 4356- total n of scores

75 * 28 = 2100 - Class A obtained

4356 - 2100 = 2256 - Class B

2256 / 32 = 70.5