How many pennies in a florin in Victorian money?

There were 12 pennies in one shilling and a florin was a two shilling piece. So, a florin was worth 24 pennies.

This is not to be confused with the later 'New Penny' introduced with decimalization in 1971. A florin is equal to £0.10, or 10 New Pence. The designation was later dropped once the original pre-decimal usage had died out.