Susie bought six pens at the office supply store and paid $4.14. larry bought a dozen of the same pens at the same store and paid $8.28.

what is the constant of variation in this situation?

4.14/6 = 0.69 cents per pen

8.28/12 = 0.69 per pen

 the constant is the price per pen

wholesale price is the initial price before markup. retail price comes after the markup.

a price of 8 bucks that's marked up by 100%   is

formula: initial price + (percent markup in fraction/decimal)(initial price)

8+(1)(8)

8+8

16

retail price is $16.