He sells the house for 1+.2=<<1+.2=1.2>>1.2 times its value
So he sells the house for 500,000*1.2=<<500000*1.2=600000>>600,000
He splits the money 1+3=<<1+3=4>>4 ways
So each person gets 600,000/4=$<<600000/4=150000>>150,000 before taxes
Taxes take away 150,000*.1=$<<150000*.1=15000>>15,000
So each person gets 150,000-15,000=$<<150000-15000=135000>>135,000
#### 135000