A trader buys 120 identical clay mugs for ₹7200. On the way home 20 of them break. At what price per mug (in ₹) must he sell the rest just to recover his money?

The whole ₹7200 has to come back from the 100 unbroken mugs, so each must fetch 7200/100 = ₹72. (₹60 is what each mug cost him — selling at that price leaves him ₹1200 short, because the broken ones earn nothing.)