JAMB 1995 · UME · Q3

The length of a notebook, 15 cm, was measured as 16.8 cm. Calculate the percentage error to 2 significant figures.

Worked solution (try it first)

The error is $16.8 - 15 = 1.8$ cm.
Divide by the true length and multiply by 100: $\frac{1.8}{15} \times 100\% = 0.12 \times 100\%$ .
So the percentage error is 12%, option A.