$1-$ It is required to remove $97\%$ of a solute C present in a mixture of $C$ in $G,$ using a solvent $L$ in an absorption tower operating in countercurrent. The inlet gas enters from the bottom and contains $8\%C,$ with a flow of $6250k\frac{g}{h}.$ The liquid solvent enters from the top at a rate of $7500k\frac{g}{h}$ and contains $4\%C.$

a$)$ Determine the concentration of solute in the solvent at the exit.