Standard costing vs variance

Good Day John

I have a question

Eg
D.Material 2tonnes @k5 per tonne

Actual production and sold 3000tonnes

Actual results:
D material bought and used 3400tonnes

Required
Calculate material usage variance

I understand from the questions you did in the open tuition on variance where standard material usage was in kgs/unit
and multiply units produced..to get the standard material usage in kgs..

Your response will be highly appreciated sir