An Australian 1985 Twenty Dollar note (Johnston/Fraser), uncirculated and in absolute mint condition could fetch up to $130 AUD. If it has been circulated but still in good condition, it might fetch anything from $30 to $50 AUD.
A reputable coin dealer will be able to give a more accurate valuation.
Twenty Australian dollars
The Australian Koala series of coins were only ever minted in platinum and the Twenty-Five Dollar coin was only ever issued as part of a set.
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.
1848. Silver. Twenty. Dollar. Coin
Such a coin would have been issued as part of a mint or proof set. Any value would depend on the metal it was struck from and the design of the coin.
There were no 1968 Australian Five Dollar notes printed.
There were no Australian Fifty Dollar notes printed in 1984.
Twenty dollars
uhhh, twenty dollars lol
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.
Such a coin would have been issued as part of a mint or proof set. Any value would depend on the metal it was struck from and the design of the coin.