∑Qt=0
Q₁+Q₂+Q₃+Q₄=0
m₁c(θ-t₁)+m₂c(θ-t₂)+m₃c(θ-t₃)+m₄c(θ-t₄)=0 |:c
m₁θ-m₁t₁+m₂θ-m₂t₂+m₃θ-m₃t₃+m₄θ-m₄t₄=0
θ(m₁+m₂+m₃+m₄)=m₁t₁+m₂t₂+m₃t₃+m₄t₄
θ=(m₁t₁+m₂t₂+m₃t₃+m₄t₄)/(m₁+m₂+m₃+m₄)=(2*10+0,5*20+1*30+3*15)/(2+0,5+1+3)=(20+10+30+150)/6,5=210/6,5=32,307° C=>θ=32,307° C