Final answer:
Sam's marks exceed the passing marks by 25%.
Step-by-step explanation:
To calculate the percentage by which Sam's marks exceed the passing marks, we need to first find the passing marks.
Since James got 250 marks and Sam scored 40% more than James, Sam's marks would be 250 + (40/100) * 250 = 250 + 100 = 350 marks.
The difference between Sam's marks and the passing marks is 350 - 280 = 70 marks.
To find the percentage, we use the formula: (difference/original) * 100 = (70/280) * 100 = 25%.
Therefore, Sam's marks exceed the passing marks by 25%, so the answer is d. 25%.