When the pressure that a gas exerts on a sealed container, with a temperature of 325 k, changes from 767 mm hg to 800 mm hg, what will the new temperature be?

Gay Lussacs law gives the relationship between pressure and temperature of gas. It states that for a fixed amount of gas the pressure is directly proportional to temperature at constant volume.
P/T = k
where P - pressure , T - temperature and k - constant 

parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
substituting these values in the equation 

T = 339 K
 new temperature is 339 K

That result from subduction of oceanic plates beneath lighter continental plates. most of the earth's volcanoes are located around the pacific ring of fire because that the location of most of the earth's subduction zones.