Use the protractor to measure these angles: m

74 marks

Step-by-step explanation:

As there are 10 girls and 20 boys, there are a total of 30 students in the class.

If the mean mark for all 30 students is 70, this means that there was a combined total score of 70 x 30 = 2100.

If the mean mark for all 10 boys was 62, this means that there was a combined total score for boys of 62 x 10 = 620.

2100 - 620 = 1480 marks in total for the girls

As there are 20 girls in the class, 1480/20 = 74

This means that the mean for the girls in the class is 74 marks.