Inequalities and word problems

Emilia needs at least $240 to buy new headphones. She has already saved $30. She earns $14 per car that she washes.

What is the least number of cars she can wash to buy the headphones?

Write the inequality to the problem.

• 14x+30 ≥ 240

• 14x+30 ≤ 240

• 30x+14 ≥ 240

• 30x+14 ≤ 240

Ruby set a goal of saving at least $200 in a savings account.

She currently has $60 in the account. If she invests $5 per week, how many weeks will it take her to reach her goal?

Write the inequality to the problem.

• 5x+60 ≥ 200

• 5x+60 ≤ 200

• 60x+5 ≥ 200

• 60x+5 ≤ 200

Jillian needs at least $4800 to buy her first car. She has already saved half. If she saves $50 per week, what is the minimum number of weeks it will take her to save enough for the car?

Write the inequality to the problem.

• 50x+1/2 ≥ 4800

• 1/2x+50 ≤ 4800

• 2400 + 50x ≥ 4800

• 50x+2400 ≤ 4800

Elliott decides to take his friends to a movie with his $50 of birthday money. He must take one adult with him. An adult ticket costs $9.75. Each child ticket cost $6.25. What is the maximum number of friends Elliott could take with him to the movies?

Write the inequality to the problem.

• 6.25x+9.75 ≥ 50

• 6.25x+9.75 ≤ 50

• 9.75x+6.25 ≥ 50

• 9.75x+6.25 ≤ 50

Which situation can be represented by the inequality
15 + 6x ≤ 100?

• Lazer Zone charges $15 plus $6 per person. If Andrea has a maximum of $100 to spend, how many people can Andrea invite to play laser tag?
• Lazer Zone charges $6 plus $15 per person. If Andrea has a maximum of $100 to spend, how many people can Andrea invite to play laser tag?
• Lazer Zone charges $15 plus $6 per person. If Andrea has a minimum of $100 to spend, how many people can Andrea invite to play laser tag?
• Lazer Zone charges $6 plus $15 per person. If Andrea has a minimum of $100 to spend, how many people can Andrea invite to play laser tag?

Joan needed $100 to buy a graphing calculator for her math class. Her neighbor will pay her $5 per hour to babysit and her Father gave her $10 for mowing the lawn. Which inequality represents the minimum amount of hours she will need to babysit in order for her to buy her calculator?

• 5x + 10 ≥ 100
• 5x - 100 ≥ 10
• 10x + 5 ≤ 100
• 5x + 10 > 100

You flip an inequality symbol when you...

• subtract
• multiply and divide only
• multiple by a negative number
• multiple or divide by a negative number

When graphing b < 6 would you use an open or closed circle?

• Open
• closed

When you graph an inequality, you used a closed dot when you use which symbols?

• ≤, ≥ 
• <, >

At the end of the day, vegetables at the farmer’s market sells for $3.00 a pound, and a basket costs $5.50. If Carol wants to buy a basket and spend no more than $10.00 total, how many pounds of vegetables can she buy?

• 3 + 5.5p < 10

• 10 = 5.5 - 3p

• 5.5 + 3p < 10

• 3p + 5.5 ≤ 10