Answer:
Sell the car for $ 3 800
Step-by-step explanation:
Thinking process:
The amount already spend = $ 4 000
a) To sell the car without additional work costs $ 5 800
The profit at that time will be $ 5 800 - $ 4 000 = $ 1 800
b) If he were to do additional work: $ 4000 + $ 2 400 = $ 6 400
That will be $ 6 400 - $ 5 800 = $ 600 (loss)
c) The loss will be better if he sells it for $ 3 800 - $ 4 000 = $ 200
So it will be better to sell it at $ 3 800 with minimum loss.