First of all I am making a number of assumptions.
1. The property passed to you after 6th april 1994.
2. The value of the land at €20,000 seems odd - value of €20,000 = IR£15,751.28. For the purposes of the exercise I will assume it is €20,000
3. There were no improvements / enhancements to the land since 1994.
Value of land in 1994 20,000
Multiplier 1.309
Value of land after applying multiplier 26,180
land sold for 96,345.47
Gain 70,165.47
Exemption 1,270
Liable to tax 68,895.47
Tax @ 20% 13,779.09
If the land was sold before 31st Dec you have to pay this amount to revenue by 31 January 06.
If sold after 1st January you have till 31 Oct 06 to pay the tax