A12 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.