If you don't want to compute Hannah's actual earning, you can just find a representative value for all the days. It can be the mean, median or mode. The easiest parameter that you can obtain without calculating is the media. Arrange the number of hours from least to greatest;
2.5 3.5 3.75 4.25 4.75
The median is 3.75. Assuming this is the number of hours for each day for 5 days, the estimated cost is:
Estimated Cost = 3.75*5*$5.85 = $109.7
Therefore, Hannah's estimate is more than the estimated cost.