The 16/45 of the students are boys who brought their lunch today.
To find the fraction of boys who brought their lunch today, we first need to find the total fraction of students who are boys, and then multiply it by the fraction of boys who brought their lunch.
Given that 8/9 of the students are boys, this means that the fraction of boys is 8/9.
Next, we are told that today, 2/5 of the boys brought their lunch.
Therefore, the fraction of boys who brought their lunch today is (8/9) * (2/5) = 16/45.
So, 16/45 of the students are boys who brought their lunch today.