Answer: To double the pressure, the temperature has to be 2*t1 K
Explanation: Gay-Lussacs law states: for a constant mass of gas held at constant volume, Pressure is proportional to absolute temperature (degrees K)
p1/t1 = p2/t2
we have p1/t1 = 2*p1/t2—> t2 = 2*p1*t1/p1 —> 2*t1