Quadratic Word Problem help! No one can help me, not Brainly, not my parents, and no one else is available!

Question

MobiStar is a mobile services company that sells 800 phones each week. when it charges $80 per phone. It sells 40 more phones per week for each $2 decrease in price. The company's revenue is the product of the number of phones sold and the price of each phone. What price should the company charge to maximize its revenue? Part A: Let d represent the number of $2 decreases in price. let r be the company's revenue. Hint: The number of phones sold will be 800+40d since they sell 40 more phones for every $2 decrease. The price for the phones will be 80-2d since d is the number of decreases and each decrease is $2. Part B: Find the vertex of the quadratic function above. How will finding the vertex help you determine at what price the company should charge to maximize its revenue? Part C: Graph this function and show in the graph what price should the company charge.

 

Part A: Let d represent the number of $2 decreases in price. let r be the company's revenue.

 

Hint: The number of phones sold will be 800+40d since they sell 40 more phones for every $2 decrease. The price for the phones will be 80-2d since d is the number of decreases and each decrease is $2.

 

Part B: Find the vertex of the quadratic function above. How will finding the vertex help you determine at what price the company should charge to maximize its revenue?

 

Part C: Graph this function and show in the graph what price should the company charge.

Answer 1

r represents revenue

d represents the number of $2 increases

 

r = (800 + 40d)(80 - 2d)

 

Can you do the rest?