Suppose a sample of radioactive substance weighs 40 mg. One year later the sample weighs 29.5 mg. What is the half life of the substance?

Use the radioactive decay formula: A = Ao*2^(-t/h), where:

A = Amt of remaining after t time

Step-by-step explanation:

Ao = Initial amt

t = time of decay

h = half-life of the substance

in this problem

A = 21.5

Ao = 38

t = 1 year

h = half life of substance