Writing Equations and Inequalties

You have $100 in your lunch account and you spend $3 per day. When your account goes below $25 a notice will be sent home to your parents. How many school days before the notice is sent?

Which inequality could be used to represent the problem?

• 100 + 3x < 25

• 100 - 3x < 25

• 25x + 100 < 3

• 100x - 3 < 25

Michael's puppy weighed 4 pounds when it was born. It gains 3 pounds per month. After how many months will the dog be at least 50 pounds?

Which inequality could be used to represent the problem?

• $3\ +\ 4x\le50$

• $4\ +\ 3x\ \le50$

• $4\ +\ 3x\ \ge50$

• $3\ +\ 4x\ \ge50$

When purchasing an iPhone XS, you need to pay a $25 activation fee in addition to a monthly charge of $33.  If the total cost of the phone is $1,250, including the activation fee, how many months will it take to pay for the entire price of the phone?

Which equation could be used to represent this situation?

• 25x + 33 = 1250

• 25 + 33x = 1250

• 1250 + 33x = 25

• 1250 + 25x = 33

Lamarka is going to the movies. She purchased a ticket for $9 and wants to buy as many boxes of candy as she can. If each box of candy is $6 and she has $33 to spend, how many boxes of candy can Lamarka buy?

If x represents the number of boxes of candy, which equation could be used to answer the question?

• 9x + 6 = 33

• 6x - 9 = 33

• 6x + 9 = 33

• 9x - 6 = 33

Michelle has $100 in her bank account. She withdraws $10 each week. How many weeks will it take for her balance to reach $20?

What equation represents the situation?

• 100 + 10x = 20

• 100 + 20x = 10

• 100 - 10x = 20

• 20x + 10 = 100