A certain volume of a gas is heated such that it's volume are now four times the original values. What's the new temperature

Answer 1

(V1/T1) = (V2/T2). I find it easier for students if we assume a volume V1 = 100 cc which makes V2 = 4*100 =400 cc. You didn't note an initial T so we call that T1, Then 100/T1 = 400/T2
100 T2 = 400 T1 and T2 = (400/100)T1 or
T2 = 4T1