Answer:
Relevant decision amounts are $9,000, $3,000 and $13,000.
Explanation:
The information which is relevant for the Product 89 is:
Sale value of the product now is $9,000
If processed further, the cost would be $3,000
Sale value after processing is $13,000
Amount $6,400 which is already spent is irrelevant for the decision as it is a sunk cost which cannot be recovered. Whether product is processed further or not, it is not going to impact the profit or loss.
Therefore, processing further will provide extra profit of $1,000 [(13,000 - 9,000) - 3,000].
Hence, it should be processed further.