In a process producing $MgS{O}_4$ salt, $800k\frac{g}{h}$ feed solution containing

$15$ wt $\%MgS{O}_4$ fed to an evaporator. Ther evaporating concertrates

the solution to $40$ wt $\%MgS{O}_4$ and evoporates some water then

the fed to a crystalyzer where crystal produce with $90wt\%MgS{O}_4$

removed The saturated solution leaving the crystalize contaning

$25$wt$\%MgS{O}_4$ recycled to the evaporator

Determine the Recycle strem r $\text{'}$s quatity.