Question$1$: with $5$cm$^2$ filter and $10$psi pressure difference between feed and permeate it is possible to sperate psp$-90$ from $70$ml solution in $3$minutes psp$-90$ is not significantly compressible.

What is required filtration time to process $300$ liters of solution at $20$psi pressure drop with $1$cm$^2$ filter?

Neglect the resistance of the filter medium.

Note the with deatials