The USS Ronald Regan's (CVN 76) barometer reads 30.14 in-hg. A vacuum gage at the port main condenser reads 18.25 in-Hg. What is the pressure relationship for this gage? What is the absolute pressure, in Psia, for the port main condensor?

Apparently the equation relationship is :

P(vac) = P(atm.) - P(abs)

But I need help to find the answers