Polly’s Pet Shop sells birds and lizards. Last week, Polly received a shipment of animals for her shop. In the shipping crate, she counted more than 20 heads and less than 70 legs. Which system of inequalities could Polly use to help her determine the possible number of birds and lizards in the crate?
A. x + y < 20 and 2x + 4y < 70
B. x + y < 20 and 2x + 4y > 70
C. x + y > 20 and 2x + 4y < 70
D. x + y > 20 and 4x + 4y < 70
Please select answer A, B, C or D.

A
Incorrect. There are more than 20 heads.

B
Incorrect. There are less than 70 legs.

C
Correct! The sum of the heads is less than 20 and the sum of the legs is less than 70.

D
Incorrect. Birds have 2 legs; lizards have 4 legs.

Maria needs to buy two types of soft drinks for a pool party. Colas cost $0.55 each and lemon-lime sodas cost $0.75 each. She plans on buying 1 drink for each guest and spending no more than $17.00. 25 people were invited to the pool party, but she is not sure everyone is attending. Which system of inequalities can be used by Maria to determine the number of each type of soft drink she could purchase?
A. x + y ≤ 25 and 0.55x + 0.75y ≤ 17
B. x + y ≥ 25 and 0.55x + 0.75y ≤ 17
C. x + y ≤ 25 and 0.55x + 0.75y ≥ 17
D. x - y ≤ 25 and 0.55x + 0.75y ≤ 17

Please select answer A, B, C or D.

A
Correct! The total number of guests is less than 25 and she will spend less than $17.00 on the drinks.

B
Incorrect. No more than 25 people will attend.

C
Incorrect. She can only spend $17.00 or less.

D
Incorrect. The total number of guests will be 25 or less.

Three times x plus two times y is less than or equal to 10. Twenty less than six times x is greater than negative three times y. Which of the following systems of inequalities is represented by the description above?
A. 3x + 2y ≤ 10 and 20 − 6x > -3y
B. 3x + 2y ≤ 10 and 6x − 20 > -3y
C. 3x + 2y < 10 and 6x − 20 > -3y
D. 3x + 2y ≤ 10 and 6x − 20 > 3y
Please select answer A, B, C or D.

A
Incorrect. Twenty is < 6x.

B
Correct! The sum of 3x and 2y is less than or equal to 10 and the difference of 6x and 20 is greater than -3y.

C
Incorrect. Less than OR equal to.

D
Incorrect. Negative three times y.

A bar-b-que restaurant sells brisket and pulled pork by the pound. They charge $13.50 per pound for brisket and $11.25 per pound for pulled pork. Last Saturday the restaurant sold more than 70 pounds of brisket and pulled pork and made a maximum of $1,000. Which system of inequalities can be used to determine the possible number of pounds of brisket and pulled pork that were sold last Saturday?
A. x + y < 70 and 13.5x + 11.25y ≤ 1000
B. x + y > 70 and 13.5x − 11.25y ≤ 1000
C. x + y > 70 and 13.5x + 11.25y ≥ 1000
D. x + y > 70 and 13.5x + 11.25y ≤ 1000
Please select answer A, B, C or D.

A
Incorrect. They sold more than 70 pounds.

B
Incorrect. The total amount of money was a maximum of $1,000.

C
Incorrect. The maximum amount of money made was $1,000.

D
Correct! The total pounds of brisket and pork is greater than 70 and the total amount of money made was less than or equal to $1,000.