Son las seis y viente is correct. Don't let anyone tell you otherwise!

6 : 20 can be translated into Spanish by substituting the Spanish words for the numbers 6 and 20.

6 is Sies

20 is veinte

Therefore the time in Spanish becomes Sies, Veinte. You can check this information on the following web page.

Translation

6 is Sies

20 is veinte

Therefore the time in Spanish becomes Sies, Veinte. You can check this information on the following web page.

Translation