area=legnth times width
in square, length=width
area living rom=12 times 18=216
area square bedrwoom=12*12=144
total=216+144=360
we don't actualy need to find the money value
bedroom/total=144/360=0.4=40/100=40%
40% spent on the bedroom
if you don't believe me
360*3.50=1260
bedroom=144*3.50=504
504/1260=0.4=40/100=40%