A partial standard cost card for the single product produced by Mercer Company is given below:

Direct materials: 3 pounds @ $8 per pound

Direct labor:? hours @? per hour

Last period the company produced 4,000 units of product. Cost and other data associated with this production are given below:

Direct materials purchased and used, at cost

$103,320

Direct labor cost incurred (10,400 hours)

$120,640

Materials price variance

$2,520

Unfavorable

Labor efficiency variance

$4,800

Unfavorable

Total labor variance

$640

Unfavorable

The direct materials purchase variance is computed when the materials are purchased.

Required:

Determine the materials quantity variance.