Write the Word or Phrase That Best Completes Each Statement

Short Answer

Write the word or phrase that best completes each statement or answers the question.
-A rumor is spread at an elementary school with 1200 students according to the model N = 1200(1 - e-0.16d)
where N is the number of students who have heard the rumor and d is the number of days that have elapsed
since the rumor began. How many days must elapse for 500 to have heard the rumor?