I am posting one question and seems to be of good quality...
A trader finds that the net profit he has made, inspite of his spring balance reading 10% less than the actual weight, is 20%. What is the markup on the cost price??
Lets assume the total cost of 1 unit of an item: $100
Since the spring shows 10% less: so the measured value of an item will be 0.9 instead of 1 unit. So, the trader will charge $90
And as given in the problem statement 90 = 1.2* x (where x is the cost price of unit)
Target selling price = cost price + markup
markup= 100-75 =$25
markup % = 25/75 = 33.33%