Finding the min value

[dzhax]

So I have a slider on my page. I need to determine the minimum amount via php.

 

I know this is more a math question than a php question.

 

I have a variable called $perCost. This variable is the cost of 1 unit.

 

I need to determine how many units must be purchased for the total cost to equal at least $minPurchase.

 

This value i will then set as the minimum value of the slider.

 

Any help on this would be much appreciated.

[Ingolme]

You haven't explained the problem well enough for me to understand. Is $minPurchase set beforehand or do we have to figure it out?

 

If you want to know how many $perCost for a $minPurchase, just do a division: $minPurchase/$perCost.

[dzhax]

yes for the sake of an example

$perCost = 0.016

$minPurchase = 0.2

Although both of these variable may change.

 

I need to determine how many full units must be purchased in order to meet the minPurchase limit.

[Ingolme]

This is elementary school math, a linear one-variable equation.

 

0.016 × x = 0.2 therefore x = 0.2÷0.016

 

Substitute it with the input variables

 

perCost × x = minPurchase therefore x = minPurchase ÷ perCost

 

The minimum amount needed to reach the price is ceil($minPurchase/$perCost). I use ceil() because if the result of the division is 1.2 you actually want 2 rather than 1.