Astudent estimated a mass to be 250g, but upon measurement found the actual mass to be 240g. what is the percent error for this measurement?

% error = 4.2 %

Percent error = |accepted mass - experimental mass|/accepted mass × 100%

∴ % error = |240 g – 250 g|/240 g × 100 % = |-10|/240 × 100 % = 4.2 %

the answer to this question is 3.