Writing Expressions?

Question

Hi could someone please give me some help with this problem? I don't know about expressions.

A retailer has a regular mark-up (profit margin) of 30% (based on the cost price). As part of a promotion, she offers a saving of $2 on every item. Using $c as the cost price:

Write an expression for the regular selling price.

Write an expression for the special promotion price.

Answer 1

If c is the item cost, and the mark up is 30%, then the mark up (m) is:

m = 30% * c = 0.30 * c

The regular selling price (p) is:

p = c + m = c + 0.30 * c = 1.30 * c

The sale price (s) is:

s = p - 2 = 1.3 * c - 2