In a fruit store there was a unique weighing machine which was made to weigh only cherries and strawberries as they were priced the same.
Other fruits like water melons or mango had different machines as they were expensive.
A man successfully buys water melons at the price of cherries. How ?
The logic used by the machines, It differentiated the fruits with the help of colour. So the weighing scale that would weigh only cherries and strawberries only weighed what was red. So the man peeled it and then weighed the fruit. Since it is red inside the machine weighs it and marks it at the price of cherries.