Answer: 35%
Step-by-step explanation:
Given
Weight measured by Leo [tex]W_1=27\ pounds[/tex]
Weight measured by the clerk [tex]W_2=20\ pounds[/tex]
Percentage error is
[tex]\Rightarrow \%\ \text{error}=\dfrac{\text{False value}-\text{Correct value}}{\text{Correct value}}\times 100[/tex]
Putting values
[tex]\Rightarrow \%\ \text{error}=\dfrac{27-20}{20}\times 100=35\%[/tex]