CSTR in series and in parallel

If the conversion achieved in a single $8d{m}^3$ CSTR is $80\%,$ what would the conversion be if the flow is equally divided into to two CSTRs in parallel with

first reactor having a volume of $4d{m}^{\text{'}}$ each $($same total volume$).$

The total reactor volume is constant at $8dm.$

If the conversion achieved in a single $8d{m}^3$ CSTR is $80\%,$ what would the

conversion be if two CSTRs are connected in series with first reactor having a

volume of approximately $3\mathrm{.}0d{m}^5$ and the second reactor having a volume of

$0\mathrm{.}6d{m}^3.$

The conversion for the two reactors in series is