Reverse feed double-effect evaporator is used to concentrate a feed of 10% solids to 20%. The heat-transfer coefficients are U₁ = 300 and U₂ = 600 btu/hr-ft^2-F for each evaporator, each of which has a surface area of 800 ft². Both the rise in boiling point and the heat of solution may be regarded as insignificant. The feed enters the 2nd evaporator at 100F, and steam enters the first evaporator number 1 at 100 psi. The 2nd evaporator's vapor space is under 2 psia of pressure. Assume that liquid water has the same thermal capacity as all other liquid solutions. Determine the solution's feed rate (F) and product rate (L1) for a 20% solids solution. Initial assumptions for feed rate and inlet steam temperature are 1000 lbm/hr and 350F. Use data from Perry's