Answer:
Net incremental cost of buying  (10,000). \
Gilberto Company should produced the parts internally . Doing so would saving its $10,000 per year
Explanation:
The relevant cash flow from the accepting the offer of the outside suppliers include
Extra variable cost of buying
Savings in direct fixed manufacturing overhead
Unit variable cost of making: =$2 Â
                                                    $
Variable cost of external purchase ($3.2× 50,000)        160,000 Â
Variable cost of making ($2× 50,000)                  (100,000 )
Extra variable cost of buying                          (60,000 )
Savings in direct fixed cost                            50,000
Net incremental cost of buying                       (10,000)