Math word problem

Sheep+sheep+sheep=45
Sheep*3=45
45/3=1 sheep
15=1 sheep

sheep + house*2=21
15-15+house*2=21-15
house*2=6
House/2=6/2
house=3
each pillar of house=1

house +candle=7
3+candle=7
3-3+candle=3-3
candle=4
each individual candle=1

3 candles+ house w/2 pillars+sheep
3+2+15
20

?=20