If the number on the right of the number you're trying to round is greater than 5, round it up. If the number on the right of the number you're trying to round is less than 5, round down.
So you're trying to round to the nearest whole number, look on the number on the right, it's bigger than 5, it's a 7. Therefore, round the whole number up so it would be 7.
12a + 6 + 3a = 15a + 2
15a = 15a - 4
0 = - 4
Using the profit concept, it is found that she makes a profit of $4 selling a dozen cookies for six dollars.
<h3>What is a profit?</h3>
The profit is given by the <u>subtraction of the revenue by the total costs</u>.
In this problem:
- For the dozen cookies, she earned a revenue of 6 dollars.
- In all, the total cost of the 12 cookies was of 0.5 + 0.7 + 0.4 + 0.4 = 2 dollars.
6 - 2 = 4, hence she makes a profit of $4.
More can be learned about the profit concept at brainly.com/question/4001746