Answer
The volume of the room has increased by a factor of 3.6
Work Step by Step
Let $W$ be the original width.
The new width is $2W$
Let $L$ be the original length.
The new length is $1.5L$
Let $H$ be the original height.
The new height is $1.2H$
The original volume was $V = WLH$
We can find the new volume $V'$:
$V' = (2W)(1.5L)(1.2H)$
$V' = 3.6~WLH$
$V' = 3.6~V$
The volume of the room has increased by a factor of 3.6