According to analysis, the oil temperature of each barrel is 20℃ higher than the temperature difference between inside and outside, which means that the room temperature is fixed, which is 20℃.

Relationship between oil temperature and cooling time:

It can be found that the oil temperature is measured every half hour, and the cooling degree is half that of the last time.

The first drop is 64℃, the second drop is 32℃, the third drop is 16℃, and then it is 8℃, 4℃ and 2℃.

So after n and a half hours, the degree of oil temperature reduction is a geometric series with 64 as the first term and 1/2 as the common ratio.

Reduced temperature △ t = [64 (1-(1/2) n)]/(1-kloc-0//2) =128 (1-(/kloc)

So t =148-△ t =128 * (1/2) n+20.

Because n and a half hours, n=t/30, substitute into the above formula, and you get

t= 148-△t= 128*( 1/2)^(t/30)+20

I'll show you later. This is more convenient. .