From the table given, the average of her longest task is 7.90 seconds while the average of her shortest task is 3.54 seconds. The difference between the two is 7.90 - 3.54 = 4.36. To the nearest tenth of a second, the answer is 4.4 second.
To find the average for each task, add all the values for each task together and divide the result by 5.
