Have you watched the free lecture on excess idle time variances? If not, then I do suggest that you do.
The expected idle time is 5% x 6,000 = 300 hours. The actual idle time is 330 hours.
Therefore there are 30 hours excess.
These are costed at the standard rate per working hour. The standard rate of pay is $10 per hour, but they are only actually expected to work for 0.95 hours. Therefore the standard work rate is 10/0.95 = 10.5263