Dry salt is to be produced at a rate of 20000 kg/h by evaporating water from a feed containing 20% NaCl. The brine (27% NaCl) leaving the evaporator may either be recycled to the evaporator or may be discarded. If the brine produced is 25% of the weight of dry salt, calculate: 

(a) The feed rate if the brine is recycled.

(b) The percent excess of the feed rate if the brine is discarded over that required when the brine is recycled.