Question

In a treatment that decreases pain and reduces inflammation of the lining of the knee joint, a sample of dysprosium-165 with an activity of 1100 counts per second was injected into the knee of a patient suffering from rheumatoid arthritis. After 24 hours, the activity had dropped to 1. 14 counts per second. Calculate the half-life of 165dy.

Answer 1

The amount of seconds dropped is 135.088 counts per second, the amount remaining is 964.912 counts per second. If you divide 964.912 by the half-life of 165dy, 1.257 minutes, you get 767.63 counts per second.

I believe the answer is 767.63 counts per second.