smc

Denote the original price of the house and the store as $h$ and $s$, respectively. It is given that $\frac{4h}{5}=\text{textdollar}12,000$, and that $\frac{6s}{5}=\text{textdollar}12,000$. Thus, $h=\text{textdollar}15,000$, $s=\text{textdollar}10,000$, and $h+s=\text{textdollar}25,000$. This value is $\text{textdollar}1000$ higher than the current price of the property, $2\cdot \text{textdollar}12,000$. Hence, the transaction resulted in a $\boxed{\text{loss of }\text{textdollar}1000}$.