Thread: functions and graphs problem solving

it costs a bicycle shop (432+87X) dollars to make x bicycles and each bicyle can be sold for (240-3x) dollars. PLEASE SHOW ALL WORKING OUT.

A) determine an expression for the total profit gained from selling x bicycles.

Originally Posted by Tessarina

it costs a bicycle shop (432+87X) dollars to make x bicycles and each bicyle can be sold for (240-3x) dollars. PLEASE SHOW ALL WORKING OUT.

A) determine an expression for the total profit gained from selling x bicycles.

Are you sure that you have transcribed that question correctly...?

As the question states:

Profit = price - cost

(-3x+240)-(87x+432)
= -3x-87x+240-432
=-90x-172

i copied the question exactly right.

but in the back of the book, the answer for the profit is:
P=-3x^2+153x-432

Originally Posted by sedemihcra

As the question states:

Profit = price - cost

(-3x+240)-(87x+432)
= -3x-87x+240-432
=-90x-172

This is almost right, but (240-3x) represents the price of one bicycle, so the total price should be x*(240-3x).

p(x) = x(-3x+240)-(87x+432)

I'm guessing that will result in the book answer.