The good old mystery

Every time again trying to solve, as always remember the correct answer.
And you poorly? )
Further explanation in pictures.
It seems to be true.

The task for the second-class parish school.
invented by Leo Tolstoy.

Now it correctly can solve only 30% of high school students,
Only 20% of university students and only 10% of employees of banks and
credit institutions

TASK
Seller sells cap. It is worth 10p. Good buyer,
it measures and agree to take it. but it has only 25 p.
The seller sends the boy with these 25 p. To change a neighbor.
Boy uses and gives 10 + 10 + 5. Seller pays cap and commissioning of 15 rubles.
After a while comes sosedkai grit that 25p. false calls to give her money.
Well che do. Seller climbs to the cashier and returned her money

Question: how much deceived seller?

the decision given moment







the buyer pays the seller 25p which in turn sends them to the exchange via the invisible Malchukov bappke



type of exchange occurs



then the seller pays 15 p cap and putting the customer and he is 10 rubles



and then let go and she bappku prosekla quarter that draw well and took from Dedkov 10p and 15P from dedkinoy stash

But losses comparable to the first frame (not forgetting the stash in 15P) and the last ...
Total Dedkov thrown at 15P stash (well, do not drink it in the evening) and shappku cost 10p ... Author: Doc_doc here