Question

There are 10 girls and 20 boys

They take a test
The mean mark for all the class is 70
The mean mark for all the boys is 62
what is the mean mark for the girls

Answer 1

The mean mark for all the girls is 86.

Explanation:

There are 30 students in all.

`(20(62) + 10g)/(30) = 70`

`1240 + 10g = 2100`

`10g = 860`

`g = 86`