 | ■No14177に返信(noppo 工学2年 さんの記事)
I don't think that this problem gives us enough physical condition.
I am answering with following assumption; the cooling rate should proportion to the defference between the liquid temperature and the ambient theperature.
It leads differential equation
dT/dt=λ(T-700)
as T ; temperature of the liquid（F)
t； cooling time (minute)
λ； constance
∫[2000,T]dT/(T-700)=λ∫[0,t]dt
log{(T-700)/1300}=λt
let T=1700 and t=3.5
λ＝(2/7)log(10/13)
let T=1000, you will get answer.
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