Jessica is selling books during the summer to earn money for college. She earns a commission on each sale but has to pay for her own expenses.

After a month of driving from neighborhood to neighborhood and walking door-to-door, she figures out that her weekly earnings are approximately a linear function of the number of doors she knocks on.

She writes the equation of the function like this: E (x) = 20x - 50, where x is the number of doors she knocks on during the week and E (x) is her earnings for the week in dollars.

What does the slope of Jessica's function represent?

a. For each additional set of books she sells, her earnings will increase by $20.

b. For each additional door she knocks on, her earnings will increase by $20.

c. For each additional set of books she sells, her earnings will increase by $50.

d. For each additional door she knocks on, her earnings will increase by $50.

Question

Mathematics

Karsyn Jefferson

17 February, 12:24

Jessica is selling books during the summer to earn money for college. She earns a commission on each sale but has to pay for her own expenses.

After a month of driving from neighborhood to neighborhood and walking door-to-door, she figures out that her weekly earnings are approximately a linear function of the number of doors she knocks on.

She writes the equation of the function like this: E (x) = 20x - 50, where x is the number of doors she knocks on during the week and E (x) is her earnings for the week in dollars.

What does the slope of Jessica's function represent?

a. For each additional set of books she sells, her earnings will increase by $20.

b. For each additional door she knocks on, her earnings will increase by $20.

c. For each additional set of books she sells, her earnings will increase by $50.

d. For each additional door she knocks on, her earnings will increase by $50.

+5

Answers (2)

Know the Answer?

Joey Hess · Answer 1

Hello there.

Jessica is selling books during the summer to earn money for college. She earns a commission on each sale but has to pay for her own expenses.

After a month of driving from neighborhood to neighborhood and walking door-to-door, she figures out that her weekly earnings are approximately a linear function of the number of doors she knocks on.

She writes the equation of the function like this: E (x) = 20x - 50, where x is the number of doors she knocks on during the week and E (x) is her earnings for the week in dollars.

b. For each additional door she knocks on, her earnings will increase by $20.

Tarzan · Answer 2

For the answer to the question above,

since the only variable used to determine earnings is the number of doors knocked, you can eliminate options 1 and 3 as they are based on the number of books sold, which is not a part of the equation.

That leaves the only options being the increase of $20 or $50 for each door knocked. As the x value we multiply by 20, the correct answer is #2, her earnings will increase by $20 for each door knocked.

You can also check this by plugging in values:

Assume 10 doors are knocked:

E (10) = 20 (10) - 50 = 200-50 = 150

Assume 11 doors (1 more door) is knocked:

E (11) = 20 (11) - 50 = 220-50 = 170

The increase from 1 door is $20.