Explanation:

The advantages of Barter System were Simplicity, More suitable in International trade, No problem of over-production and Under-production, No concentration of economic power.
Barter system is very simple, without any complications and suitable in International trade.
In this system the shortage of foreign exchange and imbalance in trade does not occur.
In barter system there is no wastage which occur in monetary economy.because goods are not over produced or under produced.Only the required quantity is produced.
The economic power is not concentrated at one particular place  in bater system because  people do not gather wealth.