If a tradesman marks his goods 25% above the cost price and allows his customers a 12% reduction on their bill, then the percentage profit he makes is ______.

10%

Let the cost price of the goods = 100

Mark up = 25% 

Marked price = 125

Reduction = 12%

Selling price of the goods = 125 × \(\frac{100 - 12}{100}\) = 125 × \(\frac{88}{100}\) = 110

Profit % = (110 - 100) ×  \(\frac{100}{100}\)  = 10%