Answer:
6 phones
Explanation:
To calculate the profit, the total revenue is subtracted by total cost.
We will calculate the company's profit as per given chart.
Quantity of phones Total revenue-total cost Profit/loss
0 0 - 90 -90 (loss)
1 200 - 170 30
2 360 - 200 160
3 480 - 290 190
4 600 - 340 260
5 700 - 400 300
6 810 - 500 310
7 910 - 620 290
The profit for selling 6 phone units is 310 which is highest.
Therefore ProPhone will need to sell six phones to maximize profit.