Q. Assertion : A number rounded off to three significant figures is , while the number would be .
Reason : In rounding off the uncertain digits, the preceding digit is raised by if the insignificant digit to be dropped is more than and is left unchanged if the latter is less than .

 2754  237 Physical World, Units and Measurements Report Error

Solution:

Correct answer is (a) If both assertion and reason are true and reason is the correct explanation of assertion