A trader sells an article at 20 percent profit. If he buys it at half of the cost price and sells at the same selling price as before, then what will be the profit percentage?
140 percent
Step 1:
\(CP_1=100,\quad SP=120,\quad CP_2=50\)
Step 2:
\(\frac{120-50}{50}\times100\%=140\%\)