Let p denote selling pricealfat wrote:a pen was sold at 10% loss.if the selling price was $ 6 more,then the seller could have made a pofit of 5%.what was the purchase price of the pen!
Let c denote purchase price (aka cost to seller)
profit = p - c
%profit = (p - c)/c = -0.1
We have two unknowns and need two formulas to solve for those unknowns. Fortunately we are given a hypothetical situation to work with:
%profit (hypothetical) = ((p+6) - c)/c = .05
Solving for p in the first formula, we get:
p = (-.1)*cost+cost = .9c
Plugging this into the second formula yields the following:
(.9c +6 - c)/c = .05
-.1c + 6 = .05c
c = 40
