Two streams of water are mixed in well stirred tank as

Area $=2m^2$

Assume $m_1,m_2^{\text{'}}$ and $m^{\text{'}}$ are constants

$(1)$ Calculat : $-(1)$ Develope a model for the process

$(2)$ if $T_1(t)=25(1+e^{-5t})$ and $T_2(t)=30(1+e^{-7t})$

where Tin$(C)$ and $t$ in second solve the model and obtain a relation for $T(t)$

$(3)$ what is $T(t)$ when $t?$