I got the ∆P in the ques but sir since she is inhaling the air

I got the ∆P in the ques but sir since she is inhaling the air, shouldn’t the pressure decrease, I mean shouldn’t it be 4-3=1 mm hg.
Please clarify my doubt sir, i think I’m missing out something very basic.

The transpulmonary pressure would be 7cm H2O when she inhales 600mL of air

Transpulmonary pressure at the begining of inhalation is 4cm H2O pulmonary compliance is 0.2L/cm H2O or 200ml/cm H2o

Therefore to expand the lungs by 200ml(or Inhalation of 200ml of air),it will require an increase in transpulmonary pressure by 1cm H2O