My guess is 30 mins sorry if wrong hope this helps
Xavier spent $84 on supplies (so this is an expense we will make only once), and then he will spend one more dollar for each canvas. So, his total expense for
paintings will be

Similarly, he will get 8 dollars for each painting, so he will earn

dollars if he will sell
paintings.
In order to break even, earnings and costs must be equal:

Subtract p from both sides:

Divide both sides by 7:

So, he has to sell at least 12 paintings to break even.
Answer: 7 marbles are green.
Step-by-step explanation:
Since we have 12 marbles in total, 12/12 = 1. Since the fractions have denominators of 12 as well, we can easily tell there are 3 yellow marbles (3/12) and there are 2 blue marbles (2/12).
Lastly, we need to find how many are green. We can subtract the yellow and blue marbles from the total of 12 marbles.
12 - (3 + 2)
12 - (5)
7 marbles are green.