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A level maths help

Can anyone help with these. Thanks in advance

A company expects to sell 20000 computers in the first year if the price of each computer is £650. Let x represent the number of £’s by which the price has decreased.
a Write an expression for the price, p, of one computer, in the form p = a + bx.
The company expects to sell an additional 50 computers every time the price decreases by £1. b Write an expression for the number of computers sold, C, in the form C = d + ex.
Revenue is defined by the formula,
revenue = (number of computers sold) × (cost of one computer) 2
c Write an equation for revenue, r, in the form A – B(x – C) , where A, B and C are constants to be found.
The company wishes to maximise the revenue.
d Using your answer to part c, or othwerwise, state the price the company should charge for each computer and the revenue they will attain.

Reply 1

Superqueen123xxx

Can anyone help pleaseee

Reply 2

old_engineer

Original post by Superqueen123xxx

Can anyone help pleaseee

What have you tried? Where are you stuck?
Also please check the exact format of the formula in part (c)

Reply 3

Superqueen123xxx

Original post by old_engineer

What have you tried? Where are you stuck?
Also please check the exact format of the formula in part (c)

For c the formula is a-b (x-c) ^2 sorry. I’m stuck on the start tbh as I don’t get how you can work out the decrease without knowing more information

Reply 4

mathstutor24

Original post by Superqueen123xxx

For c the formula is a-b (x-c) ^2 sorry. I’m stuck on the start tbh as I don’t get how you can work out the decrease without knowing more information

I think you're probably overcomplicating it. :smile:

You're given the initial price of the computer, so how would you re-write the expression with just that info first?

Now, considering that

x

should represent the number of £’s by which the price has decreased, think about (1) how to represent "decreased" in the expression, and (2) do you know enough info to enter a number for "b"?

Reply 5

Superqueen123xxx

Original post by mathstutor24

I think you're probably overcomplicating it. :smile:

You're given the initial price of the computer, so how would you re-write the expression with just that info first?

Now, considering that

x

should represent the number of £’s by which the price has decreased, think about (1) how to represent "decreased" in the expression, and (2) do you know enough info to enter a number for "b"?

So a would be the original price of 650 and obviously b would be negative if it’s decreasing. But surely you need to work out b? Or am I being really thick

Reply 6

Superqueen123xxx

Original post by mathstutor24

I think you're probably overcomplicating it. :smile:

You're given the initial price of the computer, so how would you re-write the expression with just that info first?

Now, considering that

x

should represent the number of £’s by which the price has decreased, think about (1) how to represent "decreased" in the expression, and (2) do you know enough info to enter a number for "b"?

Is the answer to part B just c = 20000 + 50x ?

Reply 7

Superqueen123xxx

If someone could just work it out I would be forever grateful

Reply 8

mathstutor24

I get what you're saying, but because they have worded it as "let x represent the NUMBER of £’s by which the price has decreased" then the coefficient b is unnecessary. Additionally, you don't have any further info that would let you calculate "b".