How many runners took at least 30 min to finish the race?
I think there are 8 people in the 30-34 category and I think 3 in the 35-39. So that's 11 people in total.
Looking at the chart (and I'll be the first to say that my eyesight is not the best at this, so make sure to use your own straightedge to verify what I'm seeing), we are looking for categories of people who took at least 30 minutes to finish the race.
We have 2 bars of people who fall into that category - the ones who took 35-39 minutes and the ones who took 30-34 minutes (we count them because they took at least 30 minutes... even the ones who took 30 minutes). We don't count any others because they are all less than 30 minutes.
Now here's where my eyesight may fail me. I think there are 8 people in the 30-34 category and I think 3 in the 35-39. So that's 11 people in total.