JAMB Mathematics 2017 Paper

Concept:Percentage error compares the size of the error to the true value as a percentage.Explanation:The actual length of the rod is $10\text{ cm}$.The measured length of the rod is $10.5\text{ cm}$.The absolute error is the difference between the measured value and the actual value.$|10.5 - 10| = 0.5\text{ cm}$.Percentage error is calculated using the formula:$$\text{Percentage error} = \frac{\text{Absolute error}}{\text{Actual value}} \times 100\%$$Substitute the values into the formula:$$\text{Percentage error} = \frac{0.5}{10} \times 100\%$$Simplify the fraction and multiply:$$\frac{0.5}{10} = 0.05$$$$0.05 \times 100\% = 5\%$$Therefore, the percentage error is $5\%$.Answer:The correct answer is A. $5\%$.