In September, Numbers Incorporated sold 50,000 units of its only product for $328,000, and incurred a total cost of $305,000, of which $33,000 was fixed costs. The flexible budget for September showed total sales of $380,000. Among variances of the period were: total variable cost flexible-budget variance, $7,000U; total flexible-budget variance, $79,000U; and, sales volume variance, in terms of contribution margin, $35,000U.

The sales volume variance, in terms of operating income, for September was: