To determine the percent volunteers that worked in the intervals mentioned, you will need to create a ratio of the number of volunteers who worked in those 2 bars to the total number of volunteers in all the bars. The number in those 2 intervals are 4+5=9, The total number of volunteer represented in the histogram is 20. This creates a fraction 9/20. TO convert this to a percent, you can create an equivalent fraction with a denominator of 100 by multiplying by 5. This means the 9 is also multiplied by 5 to make 45/100. This is equivalent to 45%. You can also divide 9 and 20 to get 0.45 (45%).
