The half-life of carbon-14 is 5730 years.

Rex the dog died in 1750. What percentage of his original carbon-14 remained in 1975 when he was found by scientists?

Suppose that the half-life of substance A is known to be . When substance A decays, it becomes substance B. If this is the only way that substance B can be produced, and a sample is found that contains of substance A and of substance B, what is the age of this sample?

A scientist discovers a new radioactive nuclei. She runs a test on a sample and finds it has an activity of . later, it has an activity of .

Determine the activity after the original reading.

A test is done on a sample of a newly discovered radioactive nuclei, which has an activity of . later, it has an activity of .

Determine the half life of this nuclei.

A scientist runs a test on a radioactive sample and finds that it has an activity of . Three days later, she runs another test and finds the activity to be .

Determine the activity of the sample 12 hours after the original reading.

The half life of is . Determine the number of radioactive nuclei in a sample with an activity of .

A scientist tests a radioactive sample which has an activity of . 15 minutes later, it has an activity of .

Determine the activity 18 minutes after the initial reading.

A new element is discovered named Banfordium. A test is run on a sample and finds it has an activity of . Three years later, the same sample has an activity of .

Determine the activity of the sample 10 years after the initial test.

The half life of is . Determine the radioactive decay constant.

If an unknown compound undergoes radioactive decay such that decays in , what is the rate constant for this reaction?