# Need Eqn for shop: cost $X, sell at £Y; Y reduced by 15% & £3; should equal £Y #### Diamond-Leopard ##### New member Need Eqn for shop: cost$X, sell at £Y; Y reduced by 15% & £3; should equal £Y

So I know when you read this you will think that I am incredibly stupid and I apologize in advance for my ignorance but hope that you will humor my stupidity.

I need an algebraic equation to help my shop...

If I buy a product for a Price, Id like to call the price 'X'

and I sell the product for a higher Price, Id like to call the price 'Y'

Now my Y value needs to be reduced by 15% and also reduced by £3 so that will give me the X value..... however I already know the X value I need to know how to get from the x Value to the Y value ???

I hope that makes sence....

So something like y=x*1.5+2?

I know that is wrong but I hope someone could help me?

#### stapel

##### Super Moderator
Staff member
I buy a product for...[cost] 'X'

and I sell the product [at]...price 'Y'

Now my Y value needs to be reduced by 15% and also reduced by £3 so that will give me the X value..... however I already know the X value I need to know how to get from the [X] [v]alue to the Y value.
Is the fifteen-percent reduction on the selling price to be taken before or after the three-pound deduction? Assuming before:

If the Y-value has been reduced by fifteen percent, then what percent remains? (here)

What expression stands for "[the remaining percentage] of [Y]"? (here)

What expression stands for "[the previous amount], less [three]"?

Set the resulting expression equal to X. Solve for "Y=". (here)

This will give you a formula for Y in terms of X.