A store lets a shopper choose between a flat ₹450 off the bill and a discount of 15% on the bill. For what bill amount (in ₹) do the two choices save exactly the same money?

The savings are equal when 15% of the bill equals ₹450, i.e. bill = $450\times 100/15=$ ₹3000. (Below ₹3000 the flat ₹450 saves more; above it the 15% does.) ₹2550 is what the shopper actually PAYS at that bill, not the bill itself, and multiplying 450 by 15 instead of dividing gives ₹6750.