1. The problem statement, all variables and given/known data A certain first-order reaction has a rate constant of 6.70×10−3 . How long will it take for the reactant concentration to drop to 1/8 of its initial value? 2. Relevant equations half life =0.693/k 3. The attempt at a solution half life = 0.693/(6.70×10−3) = 103.43 but after that I'm confused how many half lives does 1/8 refer to? I tried doing it by half life =4 but the answer came wrong. any help would be appreaciated.