Answer:
Step-by-step explanation:
Givens
The percentage error can be found with the following formula:
[tex]E_{\%} =\frac{V_{true} -V_{observed} }{V_{true}}[/tex]
Where [tex]V_{true}[/tex] refers to the expected quantity and [tex]V_{observed}[/tex] refers to the quantity in the experiment when it happens.
So, in this case, we can deduct that the true value is 20 and the observed value is 17. Replacing them, we have
[tex]E_{\%} =\frac{V_{true} -V_{observed} }{V_{true}} \times 100\%=\frac{20-17}{20} \times 100\%=\frac{3}{20} \times 100\% \\E_{\%} =0.15 \times 100\%=15\%[/tex]
Therefore, the percentage error is 15%.