EXPLANATION
The percent error formula is given by the following expression:
[tex]\text{Error}=\frac{\text{Guessed-Actual}}{\text{Actual}}\cdot100[/tex]Replacing terms:
[tex]\text{Error}=\lbrack\frac{141-150}{150}\rbrack\cdot100[/tex]Simplifying:
[tex]\text{Error}=\text{ 0.06}\cdot100=6[/tex]The percent error is 6%