The amount of beakers applied to the technology cost is dependant upon the number of civilizations which know the tech and the number of requirements you have fulfilled for the technology.
[...]
1) Multiply 0.30 by the number of KNOWN, LIVING civilizations, who have the tech.
2) Divide by the number of civilizations which STARTED on the map and ROUND DOWN to the hundredth place (0.01) of the quotient.
3) Add 2) to 1