Learn Swedish: Vad kostar virket? - What does the timber cost?

You could use virke if you were asking about the abstract price of timber in the global economy. However, when you are at a hardware store asking about the wood in front of you, Swedish requires the definite form virket (the timber).

How do I answer this question using the unit pricing rule from this lesson?

To say 'It costs 100 crowns a meter', you state the price and then use the unit of measurement in its definite singular form without a preposition. For example: Det kostar 100 kronor metern or Det kostar 500 kronor kubiken (500 crowns per cubic meter).

What is the difference between virke and trä?

Trä refers to the raw material 'wood' in general. Virke translates to 'timber' or 'lumber'—it specifically refers to wood that has been processed, cut, or prepared for construction and carpentry.

Why does the definite form end in -t instead of -en?

Virke is an ett word (ett virke). Because it is an ett word that already ends in a vowel, you simply add -t to the end to make it definite, resulting in virket.