Answer:
a. Variable cost per unit = High cost - Low cost / High volume - Low volume
Variable cost per unit = $355,880 - $228,780 / 4,960 - 1,860
Variable cost per unit = $127,100 / 3,100
Variable cost per unit = $41
b. Total cost = Fixed cost + Variable cost
$228,780 = Fixed cost + (1,860 * $41)
$228,780 = Fixed cost + $76,260
Fixed cost = $228,780 - $76,260
Fixed cost = $152,520