Gay-Lussacs law states that for a fixed amount of gas, pressure is directly proportional to absolute temperature, that is temperature in kelvin scale
[tex]\frac{P1}{T1} = \frac{P2}{T2}[/tex]
where P1 is pressure and T1 is temperature at the first instance
and P2 is pressure and T2 is temperature at the second instance
temperature has been given in the celsius scale therefore we have to convert to kelvin scale
T1 --> -15 °C + 273 = 258 K
T2 --> 46 °C + 273 = 319 K
substituting the values in the above equation
[tex]\frac{2.35 atm}{258K} = \frac{P2}{319K}[/tex]
P2 = 2.91 atm
therefore final pressure is 2.91 atm