Question

The price of a calculator depends on the number of these calculators you buy.

The table gives information about the prices of this calculator.
Number of calculators
Price of each calculator
1-29
£3.85
30-99
£3.65
100 or more
£3.49
Mr Edwards wants to buy some of these calculators.
He has £200 to spend.
Work out the greatest number of calculators he can buy.

Answer 1

1. There are many ways you can approach this problem but the easiest and most understandable way is really simple,
2. So we know that for the first 29 calculators he has to spend £3.85 on each.

So assuming he bought the entire 29 calculators he would've spent:

`29 * 3.85 = 111.65`

That leaves him with,

`200 - 111.65 = 88.35`

Looking back at the prices i'm assuming there is no way he can reach 99 calculators with what he has left, so i will establish an equation that defines the number of calculators he can buy with the remaining £88.35.

Let c be the number of calculators he can still buy. Note that we are working in the 30-99 range so each calculator costs £3.65

`88.35 = 3.65c`

`c = (88.35)/(3.65) = 24.2`

So now we know he can still buy 24 calculators in addition to the 29 calculators, so in total he bought,

`29 + 24 = 53`

Your answer would be 53 calculators.

What about the 0.2 remaining 'calculators',well that would be left over money which aren't sufficient to purchase an additional calculator+we were working with the 30-99 range meaning each one costs £3.65

`0.2 * 3.65 = 0.73`

So he bought 53 calculators and has 0.73£ remaining.

Hope this helps :)