So I've been stuck on this one for a while.

Patrick Corporation inadvertently produced 10,000 defective personal radios. The radios cost $8 each to produce. A salvage company will purchase the defective units as they are for $3 each. Patrick's production manager reports that the defects can be corrected for $5 per unit, enabling them to be sold at their regular market price of $12.50. Patrick should:

a) Sell the radios for $3 per unit.

b) Correct the defects and sell the radios at the regular price.

c) Sell the radios as they are because repairing them will cause their total cost to exceed their selling price.

d) Sell 5,000 radios to the salvage company and repair the remainder.

e) Throw the radios away.

I used the scrap or rework method and got these results-

Sell as is:

10,000 units x $3 = $30,000

Repair:

sale of reworked unit (10,000 units x ($12.50) = $125,000

less come to rework (10,000 units x $5.00) = $50,000

less opportunity cost of not making new units [10,000 x ( $12.50 - $8.00)] = $45,000

therefore, incremental income from rework = $30,000 BUT that is the same as the incremental income to scrap it.

I looked at the book answer and here is their work.

Sell as is: 10,000 units x $3 = $30,000

Repair: 10,000 units x ($12.50 - $5.00) = $75,000

So my ultimate question here is, why does this problem not include the opportunity costs of $45,000 when every other scrap or rework problem insists you include opportunity cost.