There are 10 girls and 20 boys in a class.
The class has a test.

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

Work out the mean mark for the girls.

There are 10 girls and 20 boys in a classThe class has a testThe mean mark for all the class is 70The mean mark for all the boys is 62Work out the mean mark for class=