mercury column

Problem
A gage on the suction side of a pump shown vacuum of 254 mm of mercury. Compute (a) pressure head in meters of water; (b) pressure in kiloPascal; (c) absolute pressure in kiloPascal if barometer reads 736.6 mm of mercury.
 

Problem
What height of mercury column will cause a pressure of 680 kPa? What is the equivalent height of water column?