Answer:
$11
Step-by-step explanation:
Find the incremental effect on net income of assembling the bikes as follows :
Incremental analysis for assembling the bikes per unit
Sales ( $300 - $240) $60
Less incremental costs :
Variable costs ($18)
Fixed production costs ($31)
Incremental Income/(loss) $11
Conclusion
Thus Liberty will increase its net income per unit by $11 if it opts to assemble the bikes.