Variable costs are those cost which vary with the change in production of units means higher the production higher cost and lower production will result in lower cost e.g Material cost, labor cost etc.
On the other hand fixed cost the cost which does not vary with the production of units. It is fixed no matter what is the level of production.
According to given data:
Total Cost = $500,000
Fixed Cost = $260,000
Variable cost = Total cost - fixed cost
Variable cost = $500,000 $260,000
Variable cost = $240,000
Number of units = 156,000
Variable cost per unit = $240,000 / 156,000 = $1.54 per unit