SCalcET$93\mathrm{.}8\mathrm{.}016.$

In a murder investigation, the temperature of the corpse was $32\mathrm{.}4C$ at $1$:$30p.m.$ and $30\mathrm{.}9C$ an hour later. Normal body temperature is $37\mathrm{.}0C,$ and the ambient temperature was $20\mathrm{.}0C.$ How long ago $($in minutes before $1$:$30p.m.)$ did the murder take place? $($Round your answer to the nearest minute.$)$