Twelve boys and N girls sat for a test the mean of the boys scores and that of the girls were 5 and 8 respectively, find N if the total score was 180

Since we know that there were 12 boys, and their mean score was 5, we can say that they scored a total of 60 points.

We can also say that the girls scored a total of 8N points. We can form this equation:

60 + 8N = 180

8N = 120

N = 15

Therefore, there were 15 girls.

:)