[Currency] What was the conversion rate between gold and silver?

[QuintusSertorius]

I don't have sources for this, but someone else said elsewhere:

It seems that the Achaemenids and Hellenistic kingdoms had a similar ratio [to the Roman 1/14]. One gold daric weighed around 8.3 g, and was equal to 20 silver siglos weighing 5.5 g (110 g) or 25 Attic drachmae weighing 4.3 g (108 g).

That gives us a 1:14 gold:silver ratio, more reasonable sounding than 1:27.