Answer:
3 + 1.2 c > 13.50
Step-by-step explanation:
First of all, lets write an equation that gives us the income Janie gets for doing chores. As she earns 1.20 (I will omit the $ symbol for simplicity) for each chore c she makes we can write income depending on the amount of choes as:
income(c) = 1.2 c
If she does 1 chore she gets 1.2, if she does 4 chores she gets 4.8 and so on for any c (obviously c is positive as she can do negative chores).
So, her total money will be the sum of what she earns for chores and the money she already has: 3.
money (c) = 3 + 1.2 c
If she does 2 chores she has 3+2.4=5.4 and so on for any c.
Now we need her money to be greater or equal to 13.50 in order to buy the CD. The inequality is:
money (c) > 13.50
3 + 1.2 c > 13.50
We can go further and solve it. First lets subtract 3 in both sides:
12 c > 10.50
Now, divide both sides by 1.2:
c > 10.50 / 1.2
c > 8.75
So, she needs at least 8.75 chores to earn enough money to buy the CD. As she can do fractions of chores the answer is 8.75 chores. Is she couldn't do fractions she would need at least 9 chores.