A businessman cheats by using faulty weights, to the tune of 12% each time, when buying and selling material. What is the rise in his profit percentage using faulty weights only?

25.44%

If a person cheats  x% while buying something and selling something then the profit percentage will be given by =  X + y + \(\frac{x × y}{100}\)

Given percentage = 12%

Then the profit =  12 + 12 + \(\frac{12 × 12}{100}\) = 25.44%