By applying the Newton's law of cooling and performing the neccessary calculations, the time of death of the body is about 4 hours ago.
According to the Newton's law of cooling;
T(t) = T(s) + (To - Ts)e^-kt
T(t) = temperature at time t
T(s) = temperature of the surroundings
To = Initial temperature
k = cooling constant
t = time taken
Substituting the values;
T(t) = 60 + (98.6 - 60)e^- 0.1947t
To find the time taken to attian a temperature of 78°F;
78 = 60 + (98.6 - 60)e^- 0.1947t
78= 60 + 38.6e^- 0.1947t
78 - 60 = 38.6e^- 0.1947t
18/38.6 = e^- 0.1947t
0.466 = e^- 0.1947t
ln0.466 = lne^- 0.1947t
ln0.466 =- 0.1947t
t = ln0.466 /- 0.1947
t = 4 hours
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