The bar graph above shows the number of students who were absent from Jackson High School each day last week. Of those students, 8 were absent exactly 2 days each, 1 was absent 3 days, and no students were absent more than 3 days. If 5 percent of the students were absent at least 1 day last week, how many students are enrolled in Jackson High School?
First, figure out how many total absences there were by adding up all the bars: 25 + 20 + 10 + 15 + 20 = 90.
From there, use the information you have about the students who were out multiple days to whittle the number down from total absences to total students absent. We know 1 student was out for 3 days. That means that one student was counted 3 times in the 90 number. We only want to count her once, so we’re going to subtract 2.
We also know that 8 students were each out for 2 days. Each of them was counted twice, so we need to subtract another 8.
90 – 2 – 8 = 80 students who missed at least one day.
If 80 is 5% of the total student population, then we can solve for the whole student population:
0.05x = 80
x = 1600