In a four stage compressor system first and third stage pressures are 1 and 9 kg/cm2 respectively. What will be the fourth stage delivery pressure

In a four stage compressor system first and third stage pressures are

1.	In a four stage compressor system first and third stage pressures are 1 and 9 kg/cm2 respectively. What will be the fourth stage delivery pressure
A.	243 kg/cm2
B.	81 kg/cm2
C.	3 kg/cm2
D.	27 kg/cm2
E.	9 kg/cm2
Answer» C.