question

I've found the ratios from http://www.supercars.net/garages/Duesey/40v2.html:

1st 3.15:1
2nd 2.25:1
3rd 1.68:1
4th 2.29:1
5th 1.07:1
6th 0.91:1
Final Drive ~7th gear: 0.75:1

but how can I convert them to the speeds? Sorry if seems a simple question - I should know something like this myself anyway...