\(Q_{tỏa}=Q_{thu}\Leftrightarrow m_1c_1\left(t_1-t\right)=m_2c_2\left(t-t_2\right)\)
\(\Leftrightarrow1,5.4200\left(100-t\right)=1.880.\left(t-40\right)\)
\(\Leftrightarrow6300\left(100-t\right)=880\left(t-40\right)\)
\(\Leftrightarrow7180.t=665200\)
\(\Leftrightarrow t\approx92,64\)