"Deze kleur is verkeerd."
Translation:This color is wrong.
Yes, you're both right, but it might be useful to point out that in "de verkeerde kleur" it's an adjective. If it functions as an adverb, the -e is always left out: "De kleur is verkeerd", or for just like: "Deze man is klein/slim/dom/Duits."
I found this in the notes on adverbs, Thanks.
When adjectives function as adverbs, they are not inflected:<pre>
-Kristine heeft mooi gezongen - 'Kristine has sung beautifully. -Luis heeft vandaag hard gewerkt - 'Luis has worked hard today.'</pre>