The half-life of a radioactive substance is 24 hours and there are 100 grams initially. What is the

The half-life of a radioactive substance is 24 hours and there are 100 grams initially. What is the amount of substance remaining after one week?

Using our half life calculator converting to days since 24 hours is 1 day and one week is 7 days, we have:
0.78125