Question 923626
he buys a batch of oranges at 3 oranges per rupee.
his cost per orange is equal to 1/3 of a rupee.


he buys another batch of oranges at 2 oranges per rupee.
his cost per orange is equal to 1/2 of a rupee.


since he buys an equal amount of each, then his average cost per orange for both batches is equal to (1/3 + 1/2) / 2 which is equal to 5/6 divided by 2 which is equal to 5/12 of a rupee.


his cost for 2 oranges is therefore equal to 10/12 of a rupee which can be simplified to 5/6 of a rupee.


if he sells 2 oranges for 1 rupee, then his profit is 1 - 5/6 = 1/6 of a rupee.


we can test this to see if it makes sense.


assume he buys 2 batches of 18 oranges apiece.


one batch is bought at 3 oranges per rupee for a total cost of 6 rupees.
the other batch is bought at 2 oranges per rupee for a total cost of 9 rupees.


his total cost is equal to 6 + 9 = 15 rupees.


his cost per orange is equal to 15 / 36 = 5/12 of a rupee per orange.


he sells 2.


he makes 1 rupee.
his cost is 10/12 of a rupee which simplifies to 5/6 of a rupee.
his profit is 1 rupee minus 5/6 of a rupee = 1/6 of a rupee.


solution is confirmed as good.