You estimate that a small reastarant will serve 430 customers the first week itis open the actual number of customers the first week is400 find the percent error

Percent error is calculated by the know amount minus the amount predicted over the known amount in absolute value so it would be |400-430/400| equaling to .075 which is 7.5% error

Percentage Error = (Experimental - Theorotical) / Experimental  * 100
% error = 400 - 430 / 400 * 100
% error = 30/4
% error = 7.5%

In short, Your Answer would be 7.5%

Hope this helps!

11123355543321112345566444