In order to solve this problem, you can use the Ideal Gas Law, which states that PV = nRT, where P is the pressure, V is the volume, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature in kelvin.
As we know that the volume is constant, we can say that PV1 = PV2.
P1V1 = P2V2
We also know that P1 = 30 lbs/in2, P2 = 90 lbs/in2
Rearranging the equation, we can find the temperature T2:
T2 = (P1V1/nR) * (P2/P1) = (30 lbs/in2 * V1/nR) * (90 lbs/in2/30 lbs/in2)
P1 and V1 are known. We need to find T2.
T2 = (27+273.15) * (90/30) = (300) * 3 = 900 K
So, the temperature in kelvin must be raised to 900 K in order for the can to explode.