The student council estimated that they would have 250 people attend the homecoming dance. The number of people who actually attended was 315. What is the percent error to the nearest hundredth percent

Situation: an archaelogist in turkey discovers a spear head that contains 54% of its original amount of c-14. n = noekt no = inital amount of c-14 (at time t = 0) n = amount of c-14 at time t k = 0.0001 t = time, in years find the age of the spear head to the nearest year