Not enough information.
Has it been circulated? Is there anything unique about it? Whose signature is on the front? What is the serial number?
Notes printed from 1966-1972 will have "COMMONWEALTH OF Australia" printed at the top, front and back.
Notes printed from 1972-1994 will have only "AUSTRALIA" printed at the top, front and back.
The Royal Australian Mint never issued a Twenty Dollar coin until the 1990's and then usually in a mint set of bullion coins.
The first Australian Dollar coin was issued in 1984.
There were no 1968 Australian Five Dollar notes printed.
There were no Australian Fifty Dollar notes printed in 1984.
Twenty Australian dollars
The Australian Dollar was going for about $0.73 USD in late 1994. The Australian Dollar is currently going for about $0.93 USD as of 3-Dec-2009.
The first Australian Two Dollar coin was issued in 1988.
There were no 2003 Australian Ten Dollar star notes issued.
The conversion rate between the Australian dollar and the Indian rupee is one Australian dollar to 56.42 rupees. One rupee equals 0.02 Australian dollars.
The first Australian Two Hundred Dollar coins were issued in 1980.
Such a coin does not exist. The Australian One Dollar coin was first issued in 1984.
Such a coin does not exist. The Australian Two Dollar coin was first issued in 1988.