A department store gives 10% off the whole bill, and on any bill above ₹2500 it also hands over a free hamper worth ₹250. On a bill of ₹4000 the shopper's effective discount is what percent?

The cash discount is 10% of 4000 = ₹400 and the hamper is worth another ₹250, a total benefit of ₹650 on a bill of ₹4000 = 16.25%. (The hamper must be turned into a percentage of the BILL, 250/4000 = 6.25%, before it can be added to the 10%. Dividing the ₹650 by the ₹3600 actually paid gives 18.06%, and dividing it by ₹3750 gives 17.31% — the base for a discount percent is always the original bill.)