First, let us break down 28 hours 36 minutes into minutes.
Number of minutes taken to grade 220 essays = (28 x 60) + 36 = 1680 + 36 = 1716 minutes
Now, we can find the average time taken to grade an essay by dividing the time taken to grade 220 essays by 220.
Average amount of time taken to grade an essay = [tex]\frac{1716}{220}[/tex] = 7.8 minutes, or 7 minutes and 48 seconds
