Math question help

[MissB]

I got the same as the answer sheet, but I went old school and just flipped the first part and then worked it backwards.

 

[Wolskis]

 

[Hardly Satisfied]

My brain does NOT do math!!!

This is way above my pay grade.

 

[Captain Dan]

 

[PRIMO]

30Dsquared X Square Root of Pressure equals total GPM......