Answer:
3x - 20 = 250
Step-by-step explanation:
Given,
The cost of cookies per dozen = $ 3,
Let x be the number of dozen cookies sold,
So, the cost of x dozen of cookies = x × cost of cookies per dozen
= 3x
Now, the amount of rent = $ 20,
Thus, total earning = cost of x dozen of cookies - rent
= 3x - 20
If $ 250 is needed to raise,
Then total earning = $ 250
⇒ 3x - 20 = 250
Which is the required equation.