Dear Student,
According to ideal gas equation, PV = nRT
In the question, V, R and T remains constant. Only P and n are changing
P is directly proportional to n.
n = number of moles = mass/molar mass
Molar mass in both the cases is also constant, so. P is directly proportional to mass of gas.
P1 = 10 bar, P2 = ?
m1 = 15 kg, m2 = 10 kg
After putting the values,
P2 = 6.67 bar
Pressure loss = 10-6.67 = 3.33 bar
Number of days = 4
Pressure drop per day = 3.33/4 = 0.83 bar/day
Regards