Answer:
The monthly operating advantage of purchasing internally is $20
Step-by-step explanation:
Judging from an opportunity perspective,the company pays $50 when he purchases externally and as a result saves $30,in essence the company incurs $20($50-$30) more when it purchases externally.
No doubt that if the situation reverses itself, the company gains $20 if produces and sells internally as against purchasing from external party.
From the foregoing,it is obvious that the monthly operating advantage of purchasing goods internally is a cash saving of $20 per item
Hence, buying internally is more desirable and preferred option