A 12 oz can of soda was left in a car on a hot day. in the morning, the soda temperature was 60°f with a gauge pressure of 40 psi. what will the gauge pressure be when the soda reaches 90°f (or 305 kelvin) ?

From gas equations

PV/T = Constant

Then

P1V1/T1 = P2V2/T2, but V1 = V2

Therefore,

P1/T1 = P2/T2

P2 = (P1T2) / T1

P1 = 40 psi

T1 = 60°F = 288.706 K

T2 = 90°F = 305.372 K

Substituting;

P2 = (40*305.372) / 288.706 = 42.31 psi

Then, gauge pressure would read 42.31 psi.