Every week, 2/5 of a radioactive substance remains from an initial amount of 150mg.
How many milligrams of the radioactive substance will remain after 4 weeks? Do not round your answer.
mg
After 1 week: 2/5 * 150mg = 60mg
After 2 weeks: 2/5 * 60mg = 24mg
After 3 weeks: 2/5 * 24mg = 9.6mg
After 4 weeks: 2/5 * 9.6mg = 3.84mg
After 4 weeks, 3.84mg of the radioactive substance will remain.