Loading

Answer: The boys mean mark is 72.

Explanation:Start by writing down all the information given in the question: (number of boys = 10, number of girls = 20, girls mean = 54, class mean = 60)Then have a think about anything else you might know that isn't explicitly stated: (mean = sum of all marks/total number of marks)Then create equations for the girls mean, class mean and boys mean using the information given and rearrange to solve for the boys mean (Easier to explain by working through than in words)