Question #f4db5

1 Answer
Dec 21, 2017

Answer:

T= 33,3°C

Explanation:

in first approxitation you can make a proportion:
#(T_1-T_2)/(T_1-T_f)=(T_2-T_3)/(T_2-T_f)#
that is
#(50°C-40°C)/(50°C-20°C)= (40°C- T_3)/ (40°C-20°C)#
#10/30=(40°C- T_3)/ (20°C)#
#20°C/3= (40°C- T_3)#
T3 = 33,3°C
but it is possible only because ithe time considered in the two cases are the same: 5 minutes. Otherwise you must calculate the constant of time.