An “absorber” is a device used to bring a gas containing toxic chemicals into contact with a liquid that absorbs some of those toxic chemicals from the gas. Thus, a gas stream and liquid stream enter the absorber, and a gas stream and liquid stream leave the absorber.

In an absorber you are designing, the entering gas stream flows at 340 ƒt³/min, while the gas stream leaving the absorber flows at 270 ƒt³/min. Meanwhile, the liquid stream leaving the absorber must be treated, so its flow rate is specified to be 77 lb_m/min. What mass flow rate is needed for the entering liquid stream (in units of lb_m/min)?
The densities of the entering and exiting gas streams are equal to 0.087 lb_m/ ƒt³.