81.7k views
3 votes
There are 20 boys and 10 girls in a class

they have a test

the mean mark for all the class is 70
the mean mark for the boys is 62

what is the mean mark for the girls

User TheWuif
by
7.4k points

1 Answer

2 votes

Answer:

Explanation:

AI-generated answer

To find the average score of the girls in the class, we can use the information given.

We know that there are 20 boys and 10 girls in the class. The average score of the entire class is 70, and the average score of the boys is 62.

To find the average score of the girls, we can use the concept of weighted averages. Since the average score of the entire class is 70, the total score of the class can be calculated by multiplying the average score by the number of students:

Total score of the class = Average score × Number of students

Total score of the class = 70 × (20 boys + 10 girls)

Total score of the class = 70 × 30

Total score of the class = 2100

We know that the total score of the class is 2100. Since the average score of the boys is 62, the total score of the boys can be calculated using the same formula:

Total score of the boys = Average score of the boys × Number of boys

Total score of the boys = 62 × 20

Total score of the boys = 1240

To find the total score of the girls, we subtract the total score of the boys from the total score of the class:

Total score of the girls = Total score of the class - Total score of the boys

Total score of the girls = 2100 - 1240

Total score of the girls = 860

Since there are 10 girls in the class, we can find the average score of the girls by dividing the total score of the girls by the number of girls:

Average score of the girls = Total score of the girls ÷ Number of girls

Average score of the girls = 860 ÷ 10

Average score of the girls = 86

Therefore, the average score of the girls in the class is 86.

User Jonas Pedersen
by
7.2k points