To determine the professor's efficiency in covering the chapters, we need to compare the number of chapters actually covered to the chapters expected to be covered. Efficiency can be calculated using the formula:
Efficiency = ( Expected output Actual output ) × 100
In this scenario:
Actual output : 12 chapters were covered.
Expected output : 14 chapters were expected to be covered.
Substituting these values into the formula gives:
Efficiency = ( 14 12 ) × 100
Calculating this gives:
Efficiency = ( 0.8571 ) × 100 = 85.71%
Thus, the professor's efficiency in covering the chapters is approximately 85.71%. This corresponds to covering about 86% of the expected chapters for the semester, indicating the professor was slightly less efficient due to leaving class early on Mondays and Fridays. The closest multiple-choice option is not provided, but if you want to select from the given options, you'd have to reassess the calculation or reconsider the options provided, as these seem incorrect for the scenario described.