Well stirred tank reactor of $1500$ L volume is initially filled with a solution of $0\mathrm{.}75$ mol A$/$L$.$At t$=0,$an identical solution of concentration $0\mathrm{.}25$ mol A$/$L is fed into the tank at a constant volumetric flow rate of $50$ L$/$min$.$The reaction is A$->2$B with $-$rA$=$kCA,and k$=0\mathrm{.}20$ min$^-1.$

a$)$ Assuming constant density,what will be the equation showing the concentration of A in the tank as a function of time.

b$)$Assuming constant density, what will be the equation showing the concentration of B in the tank as a function of time.