Application to Forensics
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The Case of the Murdered Accountant

A coroner uses a formula derived from Newton's Law of Cooling, a general cooling principle, to calculate the elapsed time since a person has died.  The formula is

                where T = the body's measured temperature (F)
                          Rt = the constant room temperature
                          t = is the elapsed time in hours since death

A more accurate estimate of the time of death is found by taking two readings
and averaging the two calculated times of death.

After a busy evening of income calculations an accountant was found dead in his office.  At 10 a.m. the coroner measured the body temperature to be 85.6 F.  A second reading measured at noon found the body temperature to be 82.6 F.  Assume the room was a constant 70 F.

According to the coroner what would be the estimated time of death of the accountant to the nearest minute?



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