A manometer using oil (density 0.90 g/cm3) as a fluid is connected to an air tank. Suddenly

Question:

A manometer using oil (density 0.90 g/cm3) as a fluid is connected to an air tank. Suddenly the pressure in the tank increases by 0.74 cm Hg.
(a) By how much does the fluid level rise in the side of the manometer that is open to the atmosphere?
(b) What would your answer be if the manometer used mercury instead?