Jamaal is taking a keyboarding class for school. As part of the class he needs to complete speed drills to see how fast he can type on the keyboard. In his most recent speed drill, he typed 210 words in 3½ minutes. Which of the following is an equivalent rate?

A. 240 words in 5 minutes
Incorrect. This rate is slower.

B. 200 words in 3 minutes
Incorrect. This rate is faster.

C. 300 words in 4½ minutes
Incorrect. This rate is faster.

D. 180 words in 3 minutes
Correct! Both rates are equivalent to 60 words per minute.

Four students complete a lab activity where they apply different forces to a 2 kilogram mass and measure the acceleration of the mass. Their data is recorded in the table shown below.

Which student’s data show a proportional relationship between force and acceleration?

A. Mike
Incorrect. The acceleration increases by the same amount each time, but it does not to relate to the force by a constant factor.

B. Allen
Incorrect. The acceleration increases by the same amount each time, but it does not to relate to the force by a constant factor.

C. Stephanie
Correct! The acceleration is proportional to the force.

D. Jenna
Incorrect. The force does not relate to the acceleration by a constant factor.

A grocery store is selling onions in 3-pound bags for $1.65. Which of the following bags of onions are being sold at the same price per pound as the 3-pound bag of onions?

A. A 10-pound bag for $4.95
Incorrect. This bag is less expensive per pound.

B. A 5-pound bag for $2.75.
Correct! Both bags cost $0.55 per pound.

C. A 20-pound bag for $10.45
Incorrect. This bag is less expensive per pound.

D. A 1-pound bag for $0.60
Incorrect. This bag is more expensive per pound.

Four carpet cleaning companies have published their price lists online. Which of the following companies has a price table that is based on a constant price per room?

A
Correct! The price per room is constant.

B
Incorrect. This company does not charge a constant price per room.

C
Incorrect. This company does not charge a constant price per room.

D
Incorrect. This company does not charge a constant price per room.

Jill earned $128 for 16 hours of babysitting last month. In the same month, Juan earned $165 for 22 hours of babysitting. Which statement is true?

A. Jill and Juan earn the same amount per hour for babysitting.
Incorrect. Jill earns $8 per hour, and Juan earns $7.50 per hour.

B. Jill earns $0.50 more per hour than Juan for babysitting.
Correct! Jill earns $8 per hour, and Juan earns $7.50 per hour.

C. Jill earns $0.50 less per hour than Juan for babysitting.
Incorrect. Jill earns $8 per hour, and Juan earns $7.50 per hour.

D. Jill earns $1.00 less per hour than Juan for babysitting.
Incorrect. Jill earns $8 per hour, and Juan earns $7.50 per hour.