Real-Life Math
You're just opening the door to your office when your secretary tells you the police have phoned. A body was found in the park this morning, and they need you to perform an autopsy. The coroner has requested that you find out the cause of death and the approximate time of death.
One way to determine the time of death of a body is to test the potassium levels from fluid taken from the body's eye.
Imagine the normal level of potassium in a living person is about 6 microliters. Remember that as a medical career, forensic pathology uses metric rather than imperial measurements. The amount increases the longer a person is dead, but the exact increment is different for some people.
So, to figure out this person's time of death, you will have to take 2 potassium samples 2 hours apart. Based on that 2-hour increment, you'll work back to the time at which the person's level of potassium was at a normal level to figure out roughly when the person died.
You take a sample at 2 p.m. and the potassium level is 10 microliters. You take another sample at 4 p.m. and the potassium level is 12 microliters.
With this information, you should be able to calculate the approximate time of the death.