Answer:
Variable overheads rate variance = $608 favorable
Explanation:
The variable overhead rate variance is the difference between the standard cost of the actual labour hours  and the actual variable overhead expenditure
                                             $
1,520 hours should have cost (1,520× $6.90)        10,488
But did cost                                   9,880
Rate variance                                   608 Favorable
Variable overheads rate variance = $608 favorable