A decrease of 50% every two days can be predicted with the formula x * 0.5^t x being the start amount t being time 5 days with periods of 2.5 days, 5 / 2.5 = 2 start amount of 600 600 * 0.5^2 600 * 0.25 150 so C
150 grams. If the half life is 2.5 days, then there are two half lives within five days. So, you divide 600 by half once, which is 300, and then by half again, which is 150
