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

Question

2 months ago

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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.

Mathematics

2 answers:

tester [12.3K] · Answer 1 · 2026-03-16T22:58:41+03:00

Greetings.

Jessica is selling books during the summer to earn funds for college. She earns commissions on her sales and shoulders her own costs.

After a month of visiting neighborhoods and going door-to-door, she's discovered that her earnings each week can be approximated by a linear function related to the doors she knocks on.

She expresses this relationship as E(x) = 20x - 50, where x represents the number of doors knocked in a week and E(x) reflects her weekly earnings in dollars.

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

lawyer [12.5K] · Answer 2 · 2026-03-16T22:58:03+03:00

To find the answer to the previous question,
only the number of doors knocked matters for earnings, which means options 1 and 3 can be disregarded because they pertain to book sales rather than the equation.

Thus, we're left with the possibilities of either a $20 or $50 increase for each door knocked. The x-value we multiply by is 20, making #2 the right choice; her earnings increase by $20 per door. 

You can verify this by substituting values: 

If we assume 10 doors are knocked: 
E(10) = 20(10)-50 = 200-50 = 150 

If we consider 11 doors (one additional door) knocked: 
E(11) = 20(11)-50 = 220-50 = 170 

The increase for one door is $20.

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

y = x - 3