If you remember (P1V1)/T1 = (P2V2)/T2, you can always figure any set of changes. For example, your posted problem involves only T and V; therefore, mentally remove the P1 and P2 from the formula I wrote. That leaves V1/T1 = V2/T2. You can rearrange that to V2 = V1 x T2/T1 and you can see that if T2 is larger than T1 (and increase of T), that V1 is multiplied by a factor larger than 1; therefore, V2 must increase also. .
