When you have direct variation, the best way to do calculations is find the 'rate'. In this example, 6 hours of work earned you $43.50. This means for each hour worked, you earned $43.50/6 = $7.25
Your rate of earning is $7.25 per hour. To earn $246.50, you will have to work 246.50/7.25 = 34 hours.
You can also solve this by setting up a ratio equation as follows:
$43.50 = $246.50
6 hours X hours
Solving for X, will give you X = 34 hours