Answer:
21 microwaves
Step-by-step explanation:
The net profile is equal to the income less the total cost, so the equation to the net profile NP is:
NP = 700x - (6000 + 300x)
Where 700x is the income and (6000+300x) is the cost of manufacturing.
Now, replacing NP by 2400 and solving for x, we get:
2400 = 700x - (6000 + 300x)
2400 = 700x - 6000 - 300x
2400 + 6000 = 400x
8400 = 400x
So, the least number of microwaves that must be manufactured and sold so that the net profit is $2400 is equal to 21.