Answer: 6.416%
Step-by-step explanation:
The percentage error formula is given by :-
[tex]\%\text{error}=\dfrac{|\text{Estimate-Actual}|}{\text{Actual}}\times100[/tex]
Given : The estimated weight of a substance = 475 mg
The actual weight of the substance = 445 mg
Then,
[tex]\%\text{error}=\dfrac{| 475-445|}{445}\times100\\\\=\dfrac{30}{445}\times100=6.74157303371\approx6.416\%[/tex]
Hence, the percentage error in the first weighing. = 6.416%