Please explain and solve the problem, thanks.

A BOD$5$ determination was performed using $10$ mL of a domestic wastewater sample in a $300-$mL bottle. It was discovered that the DO meter was improperly calibrated the initial DO determination; therefore, a DO determination was made $24$ hours after the sample was set. The DO was $7\mathrm{.}20$ mg$/$L$.$ The DO after $5$ days of incubation at $20$ celsius was measured at $3\mathrm{.}05$ mg$/$L$.$ The oxygen utilization rate constant at $20$ celsius for this waste is known to be $0\mathrm{.}235$ d$^-1($base e$).$ What was the BOD$5$ of this sample?It was discovered that the DO meter was improperly calibrated for the initial DO determination; therefore, a DO determination was made $24$ hours after the sample was set. The DO was $7\mathrm{.}20m\frac{g}{L}.$ The DO after $5$ days of incubation at $20C$ was measured at $3\mathrm{.}05m\frac{g}{L}.$ The oxygen utilization rate constant at $20C$ for this waste is known to be $0\mathrm{.}253d^{-1}($base e$).$ What was the $BO{D}_5$ of this sample?