What is the answer to these questions

“ Your boss has decided to make room for new models of digital cameras by discounting old models. In order to sell them quickly, she wants to sell them at the stores original cost before markup. She asked you to change the price tags and make signs with the percent of discount. Knowing that the store’s percent of markup on digital cameras is 40%, a co-worker suggests that you just mark them down by 40%

A. How would you explain to your co-worker that’s the store would actually lose money if you did this (I don’t need help with that one)
B. The original price of a camera is 175.50. What was the store’s original cost on this camera (this is the one I need help on)
C. What percent off will you write on the sign in order to sell this camera at cost? Round to the nearest percent.” I probably need help with c too but mainly b.