Question

a dugstore sells a drug costing $85 for $112 and a drug costing $175 for $238

A.) if the mark up policy of the drug store is assumed to be linear, write an equation that expresses retail price R in terms of costs( wholesale price)

B) what doews a store pay (to the nearest dollar) for a drug that retails for $185

answers:
A. R=1.4c-7
B. $137

i need solution and thanks ;)