Given pressure ,P = 511.2lb/in.2
We know that 1 atm = 760 mmHg= 14.696
lb/in.2
                     Â
So 1 lb/in.2 = (1/14.696) atm
                                       Â
= 0.068 atm
Therefore pressure , P = 511.2lb/in.2
                                   Â
= 511.2x 0.068
atm                Â
Since 1 lb/in.2=0.068 atm
                                   Â
= 34.78 atm
So the pressure in atm is 34.78 atm