How much of a radioactive kind of promethium will be left after 20 days if you start with 9,056 grams and the half-life is 5 days?
The half-life of promethium is 5 days, which means that after every 5 days, the amount of promethium will reduce by half.
After 5 days, the amount of promethium remaining will be 9,056 grams / 2 = 4,528 grams.
After another 5 days (10 days in total), the amount of promethium remaining will be 4,528 grams / 2 = 2,264 grams.
After another 5 days (15 days in total), the amount of promethium remaining will be 2,264 grams / 2 = 1,132 grams.
After another 5 days (20 days in total), the amount of promethium remaining will be 1,132 grams / 2 = 566 grams.
Therefore, after 20 days, there will be approximately 566 grams of promethium remaining.