A bag of candy was shared equally among 4 friends. Each friend gave away 7 pieces of candy. They each ended with 8 pieces of candy. Which equation represents how to find how much candy was in the bag at the beginning

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days